Superhuman anti-SARS-CoV-2 antibodies and uses thereof

ABSTRACT

This disclosure provides superhuman antibodies and antigen-binding fragments that can be administered to an individual that is infected or suspected of being infected with a virus. Superhuman antibodies and antigen-binding fragments provided herein can be capable of treating or curing the virus, and which may provide protection against the virus for up to at least several weeks. Superhuman antibodies and antigen-binding fragments provided herein can be used to diagnose a SARS Cov-2 infection.

CROSS-REFERENCE

This application claims the benefit of U.S. Provisional Application No.63/014,948, filed on Apr. 24, 2020; 63/013,485, filed Apr. 21, 2020; and62/993,630, filed Mar. 23, 2020, all of which are incorporated herein byreference in their entireties for all purposes.

SEQUENCE LISTING

The instant application contains a Sequence Listing which has been filedelectronically in ASCII format and is hereby incorporated by referencein its entirety. Said ASCII copy, created on Jun. 22, 2020, is named44561-724_201_SL.txt and is 184,726 bytes in size.

BACKGROUND OF THE INVENTION

Viruses are small infectious agents that can enter a living cell of anorganism. Genetic information from a virus can be injected into theliving cell, and can replicate inside the living cell, and be released.Viruses can cause disease in the organism and can spread betweenorganisms. The mechanism by which a virus can cause disease can varybetween viruses and can include cell lysis and/or cell death.

Coronaviruses are a group of related viruses that can cause disease, forexample in mammals and birds. Coronaviruses can cause respiratory tractinfections, such as those causing pneumonia-like diseases, that canrange from mild to lethal.

Severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) is acoronavirus responsible for a pandemic of a respiratory disease,COVID19. An outbreak of this virus was first identified in Wuhan, Hubei,China, and a pandemic was recognized by the World Health Organization onMar. 11, 2020. The range of the severity of COVID19 is large, and rangesfrom asymptomatic to death. Approximately 20% of infected individualscan require hospitalization. The mortality rate of COVID19 appears to bebetween 1% and 4%. COVID19 is transmitted between people, for examplethrough respiratory droplets, and can be spread by symptomatic andasymptomatic individuals, including during an extended incubationperiod. Social distancing has been applied worldwide to decrease thespread of COVID19.

Currently, there is no vaccine or treatment for COVID19. There is anurgent need for new compositions that can be used for treating orpreventing SARS-Cov-2 infection and for diagnosing an exposure toSARS-Cov-2 virus.

SUMMARY OF THE INVENTION

Provided herein is a superhuman (SH) antibody or antigen-bindingfragment that is derived from 2dd8, 2ghw, 3bgf, 6nb6, or CR3022, andthat selectively binds to a severe acute respiratory syndromecoronavirus 2 (SARS-CoV-2). In some embodiments, the SH antibody orantigen-binding fragment has a binding affinity of less than 50nanomolar (nM). In further embodiments, the SH antibody orantigen-binding fragment selectively binds to a receptor binding domain(RBD) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).In further embodiments, the SH antibody or antigen-binding fragmentcomprises an amino acid sequence that is at least 90%, 95%, 98%, 99%, or100% identical to a VH CDR3 comprising an amino acid sequence of any oneof any one of SEQ ID NOS: 293-316 and 429. In further embodiments, theSH antibody or antigen-binding fragment comprises further comprise anamino acid sequence that is at least 90%, 95%, 98%, 99%, or 100%identical to one or more of a VH CDR1 comprising an amino acid sequenceof any one of SEQ ID NOS: 197-220 and 430 and a VH CDR2 comprising anamino acid sequence of any one of SEQ ID NOS: 245-268 and 431.

Provided herein is an SH antibody or antigen-binding fragment asdescribed herein, that comprises a VH chain that comprises:

-   -   a. a VH CDR1 having an amino acid sequence that is at least 90%,        95%, 98%, 99%, or 100% identical to any one of SEQ ID NOS:        197-220 and 430;    -   b. a VH CDR2 having an amino acid sequence that is at least 90%,        95%, 98%, 99%, or 100% identical to any one of SEQ ID NOS:        245-268 and 431; and    -   c. a VH CDR3 having an amino acid sequence that is at least 90%,        95%, 98%, 99%, or 100% identical to any one of SEQ ID NOS:        293-316 and 429.

Provided herein is an SH antibody or antigen-binding fragment asdescribed herein, that comprises a VL chain that comprises:

-   -   a. a VL CDR1 having an amino acid sequence that is at least 90%,        95%, 98%, 99%, or 100% identical to SEQ ID NO: 29-52 and 432;    -   b. a VL CDR2 having an amino acid sequence that is at least 90%,        95%, 98%, 99%, or 100% identical to SEQ ID NO: 77-100 and 433;        and

a VL CDR3 having an amino acid sequence that is at least 90%, 95%, 98%,99%, or 100% identical to any one of SEQ ID NOS: 125-148 and 441.

Provided herein is an SH antibody or antigen-binding fragment thatcomprises (i) a VH CDR3 having an amino acid sequence that is at least90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 296; (ii) a VH CDR1having an amino acid sequence that is at least 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 200; (ii) a VH CDR2 having an amino acidsequence that is at least 90%, 95%, 98%, 99%, or 100% identical to SEQID NO: 248; (iv) a VL CDR1 having an amino acid sequence that is atleast 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 32; (v) a VLCDR2 having an amino acid sequence that is at least 90%, 95%, 98%, 99%,or 100% identical to SEQ ID NO: 80; and (vi) a VL CDR3 having an aminoacid sequence that is at least 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 128. Further provided herein is an SH antibody orantigen-binding fragment that comprises (i) a VH CDR3 having an aminoacid sequence that is at least 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 310; (ii) a VH CDR1 having an amino acid sequence that is atleast 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 214; (ii) a VHCDR2 having an amino acid sequence that is at least 90%, 95%, 98%, 99%,or 100% identical to SEQ ID NO: 262; (iv) a VL CDR1 having an amino acidsequence that is at least 90%, 95%, 98%, 99%, or 100% identical to SEQID NO: 46; (v) a VL CDR2 having an amino acid sequence that is at least90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 94; and (vi) a VLCDR3 having an amino acid sequence that is at least 90%, 95%, 98%, 99%,or 100% identical to SEQ ID NO: 142. Further provided herein is an SHantibody or antigen-binding fragment that comprises an amino acidsequence of any one of SEQ ID NOS: 5-28, a FW-L2 comprising an aminoacid sequence of any one of SEQ ID NOS: 53-76, a FW-L3 comprising anamino acid sequence of any one of any one of SEQ ID NOS: 101-124, aFW-L4 comprising amino acid of any one of SEQ ID NOS: 149-172, 435, aFW-H1 comprising an amino acid sequence of any one of SEQ ID NOS:173-196, a FW-H2 comprising amino acid sequence of any one of SEQ IDNOS: 221-244, a FW-H3 comprising an amino acid sequence of any one ofSEQ ID NOS: 269-292, and a FW-H4 comprising an amino acid sequence ofany one of SEQ ID NOS: 317-340. Further provided herein is an SHantibody or antigen-binding fragment that comprises a VH chain having anamino acid sequence that is at least 90%, 95%, 98%, 99%, or 100%identical to any one of SEQ ID NOS: 341-364 and 436. Further providedherein is an SH antibody or antigen-binding fragment that comprises a VLchain having an amino acid sequence that is at least 90%, 95%, 98%, 99%,or 100% identical to any one of SEQ ID NOS: 365-388 and 437. Furtherprovided herein is an SH antibody or antigen-binding fragment thatcomprises a VL having an amino acid sequence that is at least 90%, 95%,98%, 99%, or 100% identical to any one of SEQ ID NOS: 365-388 and 437,and a VH having an amino acid sequence that is at least 90%, 95%, 98%,99%, or 100% identical to any one of SEQ ID NOS: 341-364 and 436.Further provided herein is an SH antibody or antigen-binding fragmentthat comprises a VH having an amino acid sequence that is at least 90%,95%, 98%, 99%, or 100% identical to SEQ ID NO: 344 and a VL having anamino acid sequence that is at least 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 368. Further provided herein is an SH antibodyor antigen-binding fragment that comprises a VH having an amino acidsequence that is at least 90%, 95%, 98%, 99%, or 100% identical to SEQID NO: 358 and a VL having an amino acid sequence that is at least 90%,95%, 98%, 99%, or 100% identical to SEQ ID NO: 382. Further providedherein is an SH antibody, wherein the antibody is an IgG, an IgM, anIgE, an IgA, or an IgD, or is derived therefrom.

Provided herein is an SH antibody as described herein, wherein thebinding affinity is less than 50 nM, 49 nM, 48 nM, 47 nM, 46 nM, 45 nM,44 nM, 43 nM, 42 nM, 41 nM, 40 nM, 39 nM, 38 nM, 37 nM, 36 nM, 35 nM, 34nM, 33 nM, 32 nM, 31 nM, 30 nM, 29 nM, 28 nM, 27 nM, 26 nM, 25 nM, 24nM, 23 nM, 22 nM, 21 nM, 20 nM, 19 nM, 18 nM, 17 nM, 16 nM, 15 nM, 14nM, 13 nM, 12 nM, 11 nM, 10 nM, 9 nM, 8 nM, 7 nM, 6 nM, 5 nM, 4 nM, 3nM, 2 nM, 1 nM, 990 pM, 980 pM, 970 pM, 960 pM, 950 pM, 940 pM, 930 pM,920 pM, 910 pM, 900 pM, 890 pM, 880 pM, 870 pM, 860 pM, 850 pM, 840 pM,830 pM, 820 pM, 810 pM, 800 pM, 790 pM, 780 pM, 770 pM, 760 pM, 750 pM,740 pM, 730 pM, 720 pM, 710 pM, 700 pM, 690 pM, 680 pM, 670 pM, 660 pM,650 pM, 640 pM, 630 6M, 620 pM, 610 pM, 600 pM, 590 pM, 580 pM, 570 pM,560 pM, 550 pM, 540 pM, 530 pM, 520 pM, 510 pM, 500 pM, 490 pM, 480 pM,470 pM, 460 pM, 450 pM, 440 pM, 430 pM, 420 pM, 410 pM, 400 pM, 390 pM,380 pM, 370 pM, 360 pM, 350 pM, 340 pM, 330 pM, 320 pM, 310 pM, 300 pM,290 pM, 280 pM, 270 pM, 260 pM, 250 pM, 240 pM, 230 pM, 220 pM, 210 pM,200 pM, 190 pM, 180 pM, or any integer therebetween. Further providedherein is an SH antibody or antigen-binding fragment, wherein theantibody's antigen-binding domain or the antigen-binding fragmentcomprises a Fab, a Fab′, a F(ab′)2, a variable fragment (Fv), atriabody, a tetrabody, a minibody, a bispecific F(ab′)2, a trispecificF(ab′)2, a diabody, a bispecific diabody, a single chain variablefragment (scFv), a scFv-Fc, a Fab-Fc, a VHH, or a bispecific scFv.

Provided herein is a method of preventing or treating a SARS-CoV-2 viralinfection or COVID19 in a subject in need thereof, comprisingadministering to the subject one or more of the SH antibodies orantigen-binding fragments as described herein. Further provided hereinis a method, that further comprises administering one or more additionaltherapies or drugs to the subject. Further provided herein is a methodof diagnosing a subject as being infected with a SARS-Cov-2 virus orsuspected of being infected with a SARS-Cov-2 virus, the methodcomprising contacting a sample obtained from the subject with a SHantibody or antigen-binding fragment as described herein; detecting thepresence or absence of the SH antibody or antigen-binding fragment; anddiagnosing the subject as being infected with a SARS-CoV-2 virus whenthe presence of the SH antibody or antigen-binding fragment is detected.Further provided herein is a method, wherein the sample comprises anasal swab, a tissue sample, saliva, or blood. Further provided hereinis a method, wherein detecting the presence or absence of the SHantibody or antigen-binding fragment comprises an enzyme linkedimmunosorbent assay (ELISA), an immunospot assay, a lateral flow assay,flow cytometry, immunohistochemistry, or a western blot.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in thisspecification are herein incorporated by reference to the same extent asif each individual publication, patent, or patent application wasspecifically and individually indicated to be incorporated by reference.

BRIEF DISCLOSURE OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present disclosure will be obtained by reference tothe following detailed description that sets forth illustrativeembodiments, in which the principles of the disclosure are utilized, andthe accompanying drawings of which:

FIG. 1 provides representative viral antigen sequences.

DETAILED DESCRIPTION OF THE INVENTION

In view of the ongoing pandemic, there is a great need for therapeuticand diagnostic antibodies that selectively bind to severe acuterespiratory syndrome coronavirus 2 (SARS-Cov-2).

“2dd8” is a SARS-Cov-1 spike protein receptor binding domain. A“parental clone” or a “parental clone 2dd8” as used herein refers to anantibody that selectively binds to SARS-Cov-1 and which has thefollowing combination of complementarity determining regions (CDRs), orthe following variable heavy chain (VH), and variable light chain (VL).

2dd8 Parental CDR Sequences SEQ ID NO VH CDR1 GTFSSYTIS 389 VH CDR2MGGITPILGIANYA 390 VH CDR3 CARDTVMGGMDV 391 VL CDR1 GGNNIGSKSVH 392 VLCDR2 DDSDRPS 393 VL CDR3 QVWDSSSDYV 394

Clone VH/VL Parental CDR Sequences SEQ ID NO 2dd8 VHQVQLQQSGAEVKKPGSSVKVSCK 395 ASGGTFSSYTISWVRQAPGQGLEWMGGITPILGIANYAQKFQGRVTITT DESTSTAYMELSSLRSEDTAVYYCARDTVMGGMDVWGQGTTVTVSS 2dd8 VL SYELTQPPSVSVAPGKTARITCGGN 396NIGSKSVHWYQQKPGQAPVLVVYD DSDRPSGIPERFSGSNSGNTATLTISRVEAGDEADYYCQVWDSSSDYVFGT GTKVTVL

“2ghw” is a SARS-Cov-1 spike protein receptor binding domain. A“parental clone” or a “parental clone 2ghw” as used herein refers to anantibody that selectively binds to SARS-Cov-1 and which has thefollowing combination of CDRs, or the following variable heavy chain(VH), and variable light chain (VL).

2ghw Parental CDR Sequences SEQ ID NO VH CDR1 FAFSSYAMH 397 VH CDR2AVISYDGSNKYYA 398 VH CDR3 CARDRSYYLDY 399 VL CDR1 RASQSVRSNLA 400 VLCDR2 DASTRAT 401 VL CDR3 CQQRSNWPPT 402

Clone VH/VL Parental CDR Sequences SEQ ID NO 2ghw VH EVQLVQSGGGVVQPGKSLRLSCAAS 403 GFAFSSYAMHWVRQAPGKGLEWVAVISYDGSNKYYADSVKGRFTISRDNS KNTLYLQMNSLRAEDTAVYYCARD RSYYLDYWGQGTLVTVSS2ghw VL ETTLTQSPATLSLSPGERATLSCRASQ 404 SVRSNLAWYQQKPGQAPRPLIYDASTRATGIPDRFSGSGSGTDFTLTISRLEPED FAVYYCQQRSNWPPTFGQGTKVEVK

“3bgf” is a Middle East Respiratory Syndrome Coronavirus (MERS) spikeprotein receptor binding domain. A “parental clone” or a “parental clone3bgf” as used herein refers to an antibody that selectively binds toMERS and which has the following combination of CDRs, or the followingvariable heavy chain (VH), and variable light chain (VL).

3bgf Parental CDR Sequences SEQ ID NO VH CDR1 YTFTTYRMH 405 VH CDR2GAIYPGNSDTTYN 406 VH CDR3 CTREGIPQLLRTLDY 407 VL CDR1 RASQEISGYLS 408 VLCDR2 AASTLDS 409 VL CDR3 CLQYVSYPWT 410

Clone VH/VL Parental CDR Sequences SEQ ID NO 3bgf VHEVQLEESGTVLARPGASVKMSCKASGYTFTTYRM 411HWIKQRPGQGLEWIGAIYPGNSDTTYNQKFKDKA KLTAVTSTSSAYMELSSLTNEDSAVYFCTREGIPQLLRTLDYWGQGTSVTVSS 3bgf VL DILMTQSPSSLSASLGERVSLTCRASQEISGYLSWL 412QEKPDGTIKRLIYAASTLDSGVPKRFSGSRSGSDYS LTISSLESEDFADYYCLQYVSYPWTFGGGTKLEIK

“6nb6” is a SARS-Cov-1 spike protein receptor binding domain. A“parental clone” or a “parental clone 6nb6” as used herein refers to anantibody that selectively binds to SARS-Cov-1 and which has thefollowing combination of CDRs, or the following variable heavy chain(VH), and variable light chain (VL).

6nb6 Parental CDR Sequences SEQ ID NO VH CDR1 FTFRNYAMH 413 VH CDR2AVITSDGRNKFYA 414 VH CDR3 CVTQRDNSRDYFPHYFHDMDV 415 VL CDR1RSSQSLVYSDGDTYLN 416 VL CDR2 QVSNRDS 417 VL CDR3 CMQGSHWPPT 418

Clone VH/VL Parental CDR Sequences SEQ ID NO 6nb6 VHQVQLVESGGALVQPGRSLRLSCAASGFTFRNYAMH 419WVRQAPATGLQWLAVITSDGRNKFYADSVKGRFTI SREDSKNTLYLQMDSLRGEDTAVYYCVTQRDNSRDYFPHYFHDMDVWGQGTLVTVSS 6nb6 VL DVVLTQSPLSLPVTLGQPASISCRSSQSLVYSDGDT 420YLNWFQQRPGQSPRRLIYQVSNRDSGVPDRFSGSG SGTDFTLKISRVEAEDVGVYYCMQGSHWPPTFGQGTKVEIK

“CR3022” as referenced herein refers to an antibody that selectivelybinds to SARS-Cov-1 and which has the following combination ofcomplementarity determining regions (CDRs), or the following variableheavy chain (VH), and variable light chain (VL).

CR3022 Parental CDR Sequences SEQ ID NO VH CDR1 YGFITYWIG 421 VH CDR2GIIYPGDSETRYS 422 VH CDR3 CAGGSGISTPMDV 423 VL CDR1 KSSQSVLYSSINKNYLA424 VL CDR2 WASTRES 425 VL CDR3 CQQYYSTPYT 426

Clone VH/VL Parental CDR Sequences SEQ ID NO CR3022 VHQMQVQSGTEVKKPGESLKISCKGSGYGFITYWIGW 427VRQMPGKGLEWMGIIYPGDSETRYSPSFQGQVTISADKSINTAYLQWSSLKASDTAIYYCAGGSGISTPMDV WGQGTTVTVSS CR3022 VLDIQLTQSPDSLAVSLGERATINCKSSQSVLYSSINKN 428YLAWYQQKPGQPPKLLIYWASTRESGVPDRFSGSGSGTDFTLTISSLQAEDVAVYYCQQYYSTPYTFGQGTK VEIK

The present disclosure describes superhuman (SH) antibodies andantigen-binding fragments herein that selectively bind to SARS-Cov-2.

A SH antibody or antigen-binding fragment herein that is “derived from”these parental clones and which selectively bind to SARS-Cov-1 or MERSrefers to an antibody or antigen-binding fragment that does not compriseamino acid sequences that are 100% identical to the combination of CDRsof the parental clones, or that does not comprise amino acid sequencesthat are 100% identical to amino acid sequences of the VH and the VLsequences of the parental clones. Instead, such SH antibodies orantibody-binding fragments can have some degree of sequence identity tothe parental clones.

In one instance, SH antibodies and antigen-binding fragments herein donot contain amino acid sequences that are 100% identical to thefollowing combination of CDRs of the parental clone 2dd8 of SEQ ID NOS:389-394, or amino acid sequences that are 100% identical to the VH/VLcombination of SEQ ID NOS: 395 and 396.

In one instance, SH antibodies and antigen-binding fragments herein donot contain amino acid sequences that are 100% identical to thefollowing combination of CDRs of the parental clone 2ghw of the CDRs ofSEQ ID NOS: 397-402, or amino acid sequences that are 100% identical tothe VH/VL combination of SEQ ID NOS: 403 and 404.

In one instance, SH antibodies and antigen-binding fragments herein donot contain amino acid sequences that are 100% identical to thefollowing combination of CDRs of the parental clone 3bgf of the CDRs ofSEQ ID NOS: 405-410, or amino acid sequences that are 100% identical tothe VH/VL combination of SEQ ID NOS: 411 and 412.

In one instance, SH antibodies and antigen-binding fragments herein donot contain amino acid sequences that are 100% identical to thefollowing combination of CDRs of the parental clone 6nb6 of the CDRs ofSEQ ID NOS: 413-418, or amino acid sequences that are 100% identical tothe VH/VL combination of SEQ ID NOS: 419 and 420.

In one instance, SH antibodies and antigen-binding fragments herein donot contain amino acid sequences that are 100% identical to thefollowing combination of CDRs of the parental clone CR3022 of the CDRsof SEQ ID NOS: 421-426, or amino acid sequences that are 100% identicalto the VH/VL combination of SEQ ID NOS: 427 and 428.

As used herein, the terms “SH antibody or antigen-binding fragment” and“SH antibody or antigen-binding fragment herein which selectively bindsto the SARS-Cov-2” are synonymous.

A SH antibody or antigen-binding fragment herein also refers to anantibody or antigen-binding fragment that selectively binds toSARS-Cov-2, and which has a greater binding affinity for SARS-Cov-2 thanto SARS-Cov-1. A SH antibody or antigen-binding fragment herein that isderived from the parental clone also refers to a SH antibody orantigen-binding fragment that is capable of neutralizing the activity ofSARS-Cov-2. A SH antibody or antigen-binding fragment herein canselectively bind to the receptor binding domain (RBD) of SARS-Cov-2. Inone instance, a SH antibody or antigen-binding fragment hereinselectively binds solely to SARS-Cov-2, and not to SARS1, SARS2, and/orMiddle East Respiratory Syndrome (MERS).

Binding affinity of a SH antibody or antigen-binding fragment herein canbe determined by any suitable means including, but not limited to,high-throughput surface plasmon resonance (SPR) kinetic experiments.Briefly, a SH antibody or antigen-binding fragment herein is immobilizedto a solid surface using an anti-V5 antibody. Different concentrationsof antigen (SARS-Cov-2, SARS-Cov-1, SARS2, or MERS RBD proteins) areflowed over the immobilized SH antibodies or antigen-binding fragmentsto characterize the interactions to the immobilized SH antibodies orantigen-binding fragments. The SPR signal originates from changes in therefractive index at the surface of a gold sensor chip. An increase inmass associated with a binding event between an antibody orantigen-binding fragment and the antigen causes a proportional increasein the refractive index, which is observed as a change in response.These changes are measured as changes in the resonance angle (δθ) ofrefracted light when the antigen, flowing in a microfluidic channel,binds to the immobilized antibody and increases in density at the sensorchip. For antibody-antigen interactions, the change in refractive indexon the surface is linearly related to the number of antigens bound to animmobilized antibody. The response signal (the SPR signal) is quantifiedin resonance units (RU). When a steady-state is achieved (all bindingsites occupied), the maximum RU is determined (n: number of bindingsites in ligand). Monitoring the change in the SPR signal over timeproduces a sensorgram, a plot of the binding response (RU) versus timewhich allows different stages of a binding event to be visualized andevaluated. During the injection of an antigen, the binding responseincrease is due to the formation of antigen-antibody complexes at thesurface and the sensorgram is dominated by the association phase. Aftera certain time of injection, a steady state is reached, in which bindingand dissociating molecules are in equilibrium. The decrease in responseafter analyte injection is terminated is due to dissociation of thecomplexes, defining the dissociation phase. Depending on thedissociation rate of the tested antibody, some assays may require aregeneration step in order to reach the baseline again. Fitting thesensorgram data to an appropriate kinetic binding model allowscalculation of kinetic parameters such as the association (k_(d)) anddissociation (k_(d)) rate constants, and the binding affinity of thetested interactions.

Preferably, a SH antibody or antigen-binding fragment herein selectivelybinds to SARS-Cov-2 with a binding affinity of less than 50 nM. In oneinstance, a SH antibody or antigen-binding fragment herein canselectively bind to SARS-Cov-2 with a binding affinity of from about0.26 nM (e.g., 260 pM) to about 50 nM. In one instance, a SH antibody orantigen-binding fragment herein can selectively bind to SARS-Cov-2 witha binding affinity of less than 50 nM, 49 nM, 48 nM, 47 nM, 46 nM, 45nM, 44 nM, 43 nM, 42 nM, 41 nM, 40 nM, 39 nM, 38 nM, 37 nM, 36 nM, 35nM, 34 nM, 33 nM, 32 nM, 31 nM, 30 nM, 29 nM, 28 nM, 27 nM, 26 nM, 25nM, 24 nM, 23 nM, 22 nM, 21 nM, 20 nM, 19 nM, 18 nM, 17 nM, 16 nM, 15nM, 14 nM, 13 nM, 12 nM, 11 nM, 10 nM, 9 nM, 8 nM, 7 nM, 6 nM, 5 nM, 4nM, 3 nM, 2 nM, 1 nM, 990 pM, 980 pM, 970 pM, 960 pM, 950 pM, 940 pM,930 pM, 920 pM, 910 pM, 900 pM, 890 pM, 880 pM, 870 pM, 860 pM, 850 pM,840 pM, 830 pM, 820 pM, 810 pM, 800 pM, 790 pM, 780 pM, 770 pM, 760 pM,750 pM, 740 pM, 730 pM, 720 pM, 710 pM, 700 pM, 690 pM, 680 pM, 670 pM,660 pM, 650 pM, 640 pM, 630 6M, 620 pM, 610 pM, 600 pM, 590 pM, 580 pM,570 pM, 560 pM, 550 pM, 540 pM, 530 pM, 520 pM, 510 pM, 500 pM, 490 pM,480 pM, 470 pM, 460 pM, 450 pM, 440 pM, 430 pM, 420 pM, 410 pM, 400 pM,390 pM, 380 pM, 370 pM, 360 pM, 350 pM, 340 pM, 330 pM, 320 pM, 310 pM,300 pM, 290 pM, 280 pM, 270 pM, 260 pM, 250 pM, 240 pM, 230 pM, 220 pM,210 pM, 200 pM, 190 pM, or 180 pM, or any integer therebetween.

In any of the embodiments herein, a SH antibody or antigen-bindingfragment herein can neutralize the activity of SARS-Cov-2.Neutralization ability of a SH antibody or antigen-binding fragmentherein can be assessed using any suitable means including, but notlimited to, an in vitro pseudovirus assay. For example, spike genes froma SARS-Cov-2 virus are codon-optimized for human cells and cloned intoeukaryotic expression plasmids to generate envelope recombinantplasmids; mammalian cells are then transfected with the plasmids. Thetransfected mammalian cells are contacted with a SH antibody orantigen-binding fragment herein and trypsinization is determined as ameasure of neutralization. In some instances, a SH antibody orantigen-binding fragment herein neutralize SARS-Cov-2 by at least 5%,10%, 15%, 20%, 25%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, or more compared to a non-specific antibody, or compared to anantibody that selectively binds to SARS-Cov-1 or MERS. Neutralizationability of a SH antibody or antigen-binding fragment herein can also beassessed using, for example, an in vivo hamster animal model. Forexample, hamsters can be injected with either saline or a SH antibody orantigen-binding fragment herein. Body weight and viable signs (e.g.,ruffled hair and movement) are recorded. Viral titers are assessed inhomogenates of lung tissues and/or by immunohistochemistry of lungtissue. A SH antibody or antigen-binding fragment herein reduces viraltiters compared to controls.

Competition assay of the interaction of SARS-Cov-2 withangiotensin-converting enzyme 2 (ACE2) can be assessed using an assayincluding, but not limited to, a classical sandwich and premix assayformat. For example, anti-V5 tag antibodies are biotinylated and loadedonto streptavidin sensor tips. For a classical sandwich assay format, aSH antibody or antigen-binding fragment herein is loaded onto theanti-V5 sensor tips. Following establishment of a baseline, SARS-Cov-2is added, followed by sandwiching of ACE2 or buffer. Dissociation inbuffer is measured. Capture of biotinylated ACE2 is included as aself-blocking control. Alternatively, for a premix assay format, a SHantibody or antigen-binding fragment herein are loaded onto the anti-V5sensor tips. Following establishment of a baseline, a premix complex ofSARS-Cov-2+ACE2, or a SARS-Cov-2 alone are added to the antibodies orantigen-binding fragments. Dissociation in buffer is measured. Captureof biotinylated ACE2 is included as a self-blocking control.

Representative CDR Sequences that Selectively Bind to SARS-Cov-2

A SH antibody or antigen-binding fragment herein that selectively bindsto SARS-Cov-2 can comprise an amino acid sequence that is at least 20%,25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%,95%, 98%, 99%, or 100% identical to a VH CDR3 comprising an amino acidsequence of any one of any one of SEQ ID NOS: 293-316 and 429-320.

In some instances, a SH antibody or antigen-binding fragment herein thatselectively binds to SARS-Cov-2 can further comprise an amino acidsequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%,65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to one ormore of a VH CDR1 comprising an amino acid of any one of SEQ ID NOS:197-220 and 431-432; and a VH CDR2 comprising an amino acid sequence ofany one of SEQ ID NOS: 245-268 and 433-434.

In some instances, a SH antibody or antigen-binding fragment herein thatselectively binds to SARS-Cov-2 can further comprise an amino acidsequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%,65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to one ormore of a VL CDR1 comprising an amino acid of any one of SEQ ID NOS:29-52 and 435-436, a VL CDR2 comprising an amino acid sequence of anyone of SEQ ID NOS: 77-100 and 437-438, and a VL CDR3 comprising an aminoacid sequence of any one of SEQ ID NOS: 125-148 and 439-440.

In other instances, a SH antibody or antigen-binding fragment thatspecifically binds to a Sars-Cov-2 virus, that comprises an amino acidsequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%,65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to a VHCDR1, a VH CDR2, a VH CDR3, a VL CDR1, a VL CDR2, and a VL CDR3; whereinthe VH CDR1 has an amino acid sequence of any one of SEQ ID NOS: 197-220and 431-432; the VH CDR2 has an amino acid sequence of any one of SEQ IDNOS: 245-268 and 433-434; the VH CDR3 has an amino acid sequence of anyone of SEQ ID NOS: 293-316 and 429-420; a VL CDR1 has an amino acidsequence of any one of SEQ ID NOS: 29-52 and 435-436; a VL CDR2 has anamino acid sequence of any one of SEQ ID NOS: 77-100 and 437-438; and aVL CDR3 has an amino acid sequence of any one of SEQ ID NOS: 125-148 and441.

Representative VH CDR3 Sequences

A SH antibody or antigen-binding fragment herein that selectively bindsto SARS-CoV-2 can comprise a VH CDR3 having an amino acid sequence thatis at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to any one of thefollowing sequences:

Clone ID VH CDR3 SEQ ID NO: COVID19_P23_F10 CAIGTTVVTPFGYW 293COVID19_P24_H06 CARGQVRGSGPQVVVMDVW 294 COVID19_P24_F11 CAKDGTLITTTLDYW295 COVID19_P23_G11 CARAGYSSSSGYYYYGMDVW 296 COVID19_P24_D09CARVRGSAAIAMMDVW 297 COVID19_P11_H02 CASFERFGELVPETFDYW 298COVID19_P24_C06 CARDRGSYDTDAFDIW 299 COVID19_P12_B07 CASAHSSSWYSDWFDPW300 COVID19_P24_H04 CAGMGMGRDGYNSRAFDIW 301 COVID19_P23_G10CARVDYGDYGRLEDYW 302 COVID19_P24_A09 CARLEGGSYWTGYFDLW 303COVID19_P11_D12 CAKTRYGGNSRSRYYYYGMDVW 304 COVID19_P24_A11CARDLMDIVVVPWLGGMDVW 305 COVID19_P24_C10 CARD SGVDTATLRYYYYGMDVW 306COVID19_P11_D08 CARDSGVDTATLRYYYYGMDVW 307 COVID19_P24_E02CAKDVQNYYGSGSSFDYW 308 COVID19_P23_H10 CARGSSGYYFGW 309 COVID19_P24_G06CTTDPVLEWFGYSIW 310 COVID19_P24_C01 CAKGAPHDYIWGSYRPDAFDIW 311COVID19_P24_G09 CAKGAPHDYIWGSYRPDAFDIW 312 COVID19_P24_D08 CATVTPGYGMDVW313 COVID19_P11_H07 CARGWMAYDAFDIW 314 COVID19_P11_G03CARDRGYSYDHDQIYYYYGMDVW 315 COVID19_P24_B09 CARDRGDTIDYW 316COVID19_P23_G12 CARDRGSYDTDAFDIW 429 Representative VH CDR1 sequences

A SH antibody or antigen-binding fragment herein that selectively bindsto SARS-CoV-2 can comprise a VH CDR1 having an amino acid sequence thatis at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to any one of thefollowing sequences:

Clone ID VH CDR1 SEQ ID NO: COVID19_P23_F10 DTFSNYGIS 197COVID19_P24_H06 FSFSNYDMH 198 COVID19_P24_F11 FTFSGSAMH 199COVID19_P23_G11 GTFRSTAIS 200 COVID19_P24_D09 GTFSSYAIS 201COVID19_P11_H02 GTFTSYHMH 202 COVID19_P24_C06 YIFTSYPIH 203COVID19_P12_B07 YTFINYDIN 204 COVID19_P24_H04 YTFTDYHMH 205COVID19_P23_G10 YTFTDYYIQ 206 COVID19_P24_A09 YTFTDYYMQ 207COVID19_P11_D12 YTFTENEMH 208 COVID19_P24_A11 YTFTENEMH 209COVID19_P24_C10 YTFTENEMH 210 COVID19_P11_D08 YTFTENEMH 211COVID19_P24_E02 YTFTGNYIH 212 COVID19_P23_H10 YTFTGSYAIS 213COVID19_P24_G06 YTFTNYGIS 214 COVID19_P24_C01 YTFTRYYIH 215COVID19_P24_G09 YTFTRYYIH 216 COVID19_P24_D08 YTFTSYDIN 217COVID19_P11_H07 YTFTSYDIN 218 COVID19_P11_G03 YTFTSYEIN 219COVID19_P24_B09 YTFTSYGIS 220 COVID19_P23_G12 YIFTSYPIH 430

Representative VH CDR2 Sequences

A SH antibody or antigen-binding fragment herein that selectively bindsto SARS-CoV-2 can comprise a VH CDR2 having an amino acid sequence thatis at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to any one of thefollowing sequences:

Clone ID VH CDR2 SEQ ID NO: COVID19_P23_F10 GWMNPNSGGTNYA 245COVID19_P24_H06 AVISYDGGFKLYA 246 COVID19_P24_F11 SAISRNGGTTYYA 247COVID19_P23_G11 GWMNPNSGNTGYA 248 COVID19_P24_D09 GIVNPSSGSTTYA 249COVID19_P11_H02 GWMNPNSGNTGYA 250 COVID19_P24_C06 GWMNPNSGNTGYA 251COVID19_P12_B07 GVINPSAGSTSYA 252 COVID19_P24_H04 GWMNPNSGNTSYA 253COVID19_P23_G10 GWINPNSGGPNYA 254 COVID19_P24_A09 GWIDPHSGATNYA 255COVID19_P11_D12 GIINPSGGSTSYA 256 COVID19_P24_A11 GIINPSGGSTSYA 257COVID19_P24_C10 GIINPSGGSTSYA 258 COVID19_P11_D08 GIINPSGGSTSYA 259COVID19_P24_E02 GWMNPNSGNTGYA 260 COVID19_P23_H10 GWINPKTGDTNYA 261COVID19_P24_G06 GWISARNGNTNYA 262 COVID19_P24_C01 GIINPSGGSTTYA 263COVID19_P24_G09 GIINPSGGSTTYA 264 COVID19_P24_D08 GIIDPSGGSTSYA 265COVID19_P11_H07 GWMNSNSGSTGYA 266 COVID19_P11_G03 GIINPSDGSSTYA 267COVID19_P24_B09 GGIIPMFGTTNYA 268 COVID19_P23_G12 GWMNPNSGNTGYA 431

Representative VL CDR1 Sequences

A SH antibody or antigen-binding fragment herein that selectively bindsto SARS-CoV-2 can comprise a VL CDR1 having an amino acid sequence thatis at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to any one of thefollowing sequences:

Clone ID VL CDR1 SEQ ID NO: COVID19_P23_F10 RASESVSSRYLA 29COVID19_P24_H06 QASQGIRNDLG 30 COVID19_P24_F11 RAS QSIGYYLN 31COVID19_P23_G11 RASQGISNNLN 32 COVID19_P24_D09 RASQDIRNELG 33COVID19_P11_H02 RASQGIRNDLA 34 COVID19_P24_C06 RASQDISNYLN 35COVID19_P12_B07 RASQSISSYLN 36 COVID19_P24_H04 RASQSISTYLN 37COVID19_P23_G10 RASQSIYSWLA 38 COVID19_P24_A09 RASQSVSSNYLA 39COVID19_P11_D12 RASQHISSYLN 40 COVID19_P24_A11 RASQAITNYLA 41COVID19_P24_C10 QASQDISKYLN 42 COVID19_P11_D08 QASQDISKYLN 43COVID19_P24_E02 RASQGIRNYLA 44 COVID19_P23_H10 RASQSISSYLN 45COVID19_P24_G06 KSSQSVFSSSNNKNYLA 46 COVID19_P24_C01 RASENIDSWLA 47COVID19_P24_G09 RASENIDSWLA 48 COVID19_P24_D08 RASQTIYSYLN 49COVID19_P11_H07 QASQSIYNYLN 50 COVID19_P11_G03 RVSQGISSYLN 51COVID19_P24_B09 RASQGISNNLN 52 COVID19_P23_G12 RASQDISNYLN 432

Representative VL CDR2 sequences

A SH antibody or antigen-binding fragment herein that selectively bindsto SARS-CoV-2 can comprise a VL CDR2 having an amino acid sequence thatis at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to any one of thefollowing sequences:

Clone ID VL CDR2 SEQ ID NO: COVID19_P23_F10 GASTRAT 77 COVID19_P24_H06DASRLQS 78 COVID19_P24_F11 AASSLQS 79 COVID19_P23_G11 AASSLQS 80COVID19_P24_D09 AASSLQS 81 COVID19_P11_H02 AASSLQS 82 COVID19_P24_C06AASNLQS 83 COVID19_P12_B07 AASSLQS 84 COVID19_P24_H04 AASTLQS 85COVID19_P23_G10 DASSLES 86 COVID19_P24_A09 AVSSRAT 87 COVID19_P11_D12AASALQS 88 COVID19_P24_A11 AASSLQS 89 COVID19_P24_C10 GASTLSD 90COVID19_P11_D08 GASTLSD 91 COVID19_P24_E02 AASTLQS 92 COVID19_P23_H10AASRLQS 93 COVID19_P24_G06 WASTRES 94 COVID19_P24_C01 EASTLES 95COVID19_P24_G09 EASTLES 96 COVID19_P24_D08 DASNLET 97 COVID19_P11_H07DASNLET 98 COVID19_P11_G03 AASILQS 99 COVID19_P24_B09 AASSLES 100COVID19_P23_G12 AASNLQS 433

Representative VL CDR3 Sequences

A SH antibody or antigen-binding fragment herein that selectively bindsto SARS-CoV-2 can comprise a VL CDR3 having an amino acid sequence thatis at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to any one of thefollowing sequences:

Clone ID VL CDR3 SEQ ID NO: COVID19_P23_F10 CQQGYKNPPTF 125COVID19_P24_H06 CQQYYSTPPLTF 126 COVID19_P24_F11 CQQSYTTPLTF 127COVID19_P23_G11 CQQYDTFPLTF 128 COVID19_P24_D09 CQQSYSTPPWTF 129COVID19_P11_H02 CQQSYSTPPTF 130 COVID19_P24_C06 CQQANSFPSTF 131COVID19_P12_B07 CQQSYSTPLTF 132 COVID19_P24_H04 CQQSYSMPLTF 133COVID19_P23_G10 CQQLNSYPYTF 134 COVID19_P24_A09 CQQYGSSPLTF 135COVID19_P11_D12 CQQGYGTPYTF 136 COVID19_P24_A11 CQQYYSYPPTF 137COVID19_P24_C10 CQQGYSTPYSF 138 COVID19_P11_D08 CQQGYSTPYSF 139COVID19_P24_E02 CQQSYSPPLTF 140 COVID19_P23_H10 CQQSYSTPLTF 141COVID19_P24_G06 CQQYYSTPLTF 142 COVID19_P24_C01 CHQYLSSPETF 143COVID19_P24_G09 CHQYLSSPETF 144 COVID19_P24_D08 CQQAISFPLTF 145COVID19_P11_H07 CQQAISFPLTF 146 COVID19_P11_G03 CQQGYSTPFTF 147COVID19_P24_B09 CQQGNGFPLTF 148 COVID19_P23_G12 CQQANSFPSTF 441

Representative CDR Combinations

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 293; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 197; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 245; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 29; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 77; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 125.

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 294; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 198; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 246; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 30; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 78; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 126.

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 295; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 199; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 247; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 31; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 79; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 127.

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 296; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 200; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 248; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 32; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 80; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 128.

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 297; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 201; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 249; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 33; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 81; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 129.

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 298; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 202; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 250; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 34; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 82; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 130.

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 299; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 203; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 251; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 35; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 83; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 131.

In one instance, the antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 300; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 204; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 252; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 36; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 84; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 132.

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 301; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 205; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 253; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 37; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 85; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 133.

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 302; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 206; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 254; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 38; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 86; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 134.

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 303; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 207; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 255; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 39; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 87; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 135.

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 304; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 208; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 256; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 40; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 88; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 136.

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 305; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 209; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 257; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 41; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 89; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 137.

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 306; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 210; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 258; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 42; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 90; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 138.

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 307; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 211; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 259; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 43; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 91; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 139.

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 308; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 212; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 260; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 44; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 92; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 140.

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 309; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 213; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 261; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 45; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 93; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 141.

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 310; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 214; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 262; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 46; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 94; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 142.

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 311; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 215; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 263; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 47; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 95; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 143.

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 312; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 216; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 264; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 48; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 96; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 144.

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 313; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 217; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 265; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 49; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 97; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 145.

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 314; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 218; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 266; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 50; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 98; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 146.

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 315; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 219; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 267; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 51; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 99; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 147.

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 316; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 220; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 268; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 52; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 100; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 148.

In one instance, the SH antibody or antigen-binding fragment thatselectively binds to SARS-Cov-2 can comprise (i) a VH CDR3 having anamino acid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identicalto SEQ ID NO: 429; (ii) a VH CDR1 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 430; (ii)a VH CDR2 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 431; (iv) a VL CDR1 having an aminoacid sequence that is at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical toSEQ ID NO: 432; (v) a VL CDR2 having an amino acid sequence that is atleast 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 98%, 99%, or 100% identical to SEQ ID NO: 433; and (vi) aVL CDR3 having an amino acid sequence that is at least 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%,99%, or 100% identical to SEQ ID NO: 441.

Representative Superhuman (SH) Frameworks (FW) of Antibodies andAntigen-Binding Fragments that Selectively Bind to SARS-CoV-2

A SH antibody or antigen-binding fragment herein that selectively bindsto SARS-Cov-2 can comprise an amino acid sequence that is at least 20%,25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%,95%, 98%, 99%, or 100% identical to one or more of a FW-L1 comprising anamino acid sequence of any one of SEQ ID NOS: 5-28, a FW-L2 comprisingan amino acid sequence of any one of SEQ ID NOS: 53-76, a FW-L3comprising an amino acid sequence of any one of any one of SEQ ID NOS:101-124, a FW-L4 comprising amino acid of any one of SEQ ID NOS:149-172, 435, a FW-H1 comprising an amino acid sequence of any one ofSEQ ID NOS: 173-196, a FW-H2 comprising amino acid sequence of any oneof SEQ ID NOS: 221-244, a FW-H3 comprising an amino acid sequence of anyone of SEQ ID NOS: 269-292, and a FW-H4 comprising an amino acidsequence of any one of SEQ ID NOS: 317-340.

Representative FW-L1 Sequences

A SH antibody or antigen-binding fragment herein that selectively bindsto SARS-CoV-2 can comprise a (FW-L1) having an amino acid sequence thatis at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to any one of thefollowing sequences:

Clone ID FW-L1 SEQ ID NO: COVID19_P23_F10 EIVMTQSPATLSVSPGERATLSC 5COVID19_P24_H06 DIQMTQSPSSLSASVGDRVTITC 6 COVID19_P24_F11DIQMTQSPSSLSASVGDRVTITC 7 COVID19_P23_G11 DIQMTQSPSSLSASVGDRVTITC 8COVID19_P24_D09 DIQMTQSPSSLSASVGDRVTITC 9 COVID19_P11_H02DIQMTQSPSSLSASVGDRVTITC 10 COVID19_P24_C06 DIQMTQSPSSLSASVGDRVTITC 11COVID19_P12_B07 DIQMTQSPSSLSASVGDRVTITC 12 COVID19_P24_H04DIQMTQSPSSLSASVGDRVTITC 13 COVID19_P23_G10 DIQMTQSPSSLSASVGDRVTITC 14COVID19_P24_A09 EIVMTQSPATLSVSPGERATLSC 15 COVID19_P11_D12DIQMTQSPSSLSASVGDRVTITC 16 COVID19_P24_A11 DIQMTQSPSSLSASVGDRVTITC 17COVID19_P24_C10 DIQMTQSPSSLSASVGDRVTITC 18 COVID19_P11_D08DIQMTQSPSSLSASVGDRVTITC 19 COVID19_P24_E02 DIQMTQSPSSLSASVGDRVTITC 20COVID19_P23_H10 DIQMTQSPSSLSASVGDRVTITC 21 COVID19_P24_G06DIVMTQSPDSLAVSLGERATINC 22 COVID19_P24_C01 DIQMTQSPSSLSASVGDRVTITC 23COVID19_P24_G09 DIQMTQSPSSLSASVGDRVTITC 24 COVID19_P24_D08DIQMTQSPSSLSASVGDRVTITC 25 COVID19_P11_H07 DIQMTQSPSSLSASVGDRVTITC 26COVID19_P11_G03 DIQMTQSPSSLSASVGDRVTITC 27 COVID19_P24_B09DIQMTQSPSSLSASVGDRVTITC 28 COVID19_P23_G12 DIQMTQSPSSLSASVGDRVTITC 28

Representative FW-L2 Sequences

A SH antibody or antigen-binding fragment herein that selectively bindsto SARS-CoV-2 can comprise a FW-L2 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to any one of thefollowing sequences:

Clone ID FW-L2 SEQ ID NO: COVID19_P23_F10 WYQQKPGQAPRLLIY 53COVID19_P24_H06 WYQQKPGKAPKLLIY 54 COVID19_P24_F11 WYQQKPGKAPKLLIY 55COVID19_P23_G11 WYQQKPGKAPKLLIY 56 COVID19_P24_D09 WYQQKPGKAPKLLIY 57COVID19_P11_H02 WYQQKPGKAPKLLIY 58 COVID19_P24_C06 WYQQKPGKAPKLLIY 59COVID19_P12_B07 WYQQKPGKAPKLLIY 60 COVID19_P24_H04 WYQQKPGKAPKLLIY 61COVID19_P23_G10 WYQQKPGKAPKLLIY 62 COVID19_P24_A09 WYQQKPGQAPRLLIY 63COVID19_P11_D12 WYQQKPGKAPKLLIY 64 COVID19_P24_A11 WYQQKPGKAPKLLIY 65COVID19_P24_C10 WYQQKPGKAPKLLIY 66 COVID19_P11_D08 WYQQKPGKAPKLLIY 67COVID19_P24_E02 WYQQKPGKAPKLLIY 68 COVID19_P23_H10 WYQQKPGKAPKLLIY 69COVID19_P24_G06 WYQQKPGQPPKLLIY 70 COVID19_P24_C01 WYQQKPGKAPKLLIY 71COVID19_P24_G09 WYQQKPGKAPKLLIY 72 COVID19_P24_D08 WYQQKPGKAPKLLIY 73COVID19_P11_H07 WYQQKPGKAPKLLIY 74 COVID19_P11_G03 WYQQKPGKAPKLLIY 75COVID19_P24_B09 WYQQKPGKAPKLLIY 76 COVID19_P23_G12 WYQQKPGKAPKLLIY 76

Representative FW-L3 Sequences

A SH antibody or antigen-binding fragment herein that selectively bindsto SARS-CoV-2 can comprise a FW-L3 having an amino acid sequence o thatis at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to any one of thefollowing sequences:

Clone ID FW-L3 SEQ ID NO: COVID19_P23_F10GIPARFSGSGSGTEFTLTISSLQSEDFAVYY 101 COVID19_P24_H06GVPSRFSGSGSGTDFTLTISSLQPEDFATYY 102 COVID19_P24_F11GVPSRFSGSGSGTDFTLTISSLQPEDFATYY 103 COVID19_P23_G11GVPSRFSGSGSGTDFTLTISSLQPEDFATYY 104 COVID19_P24_D09GVPSRFSGSGSGTDFTLTISSLQPEDFATYY 105 COVID19_P11_H02GVPSRFSGSGSGTDFTLTISSLQPEDFATYY 106 COVID19_P24_C06GVPSRFSGSGSGTDFTLTISSLQPEDFATYY 107 COVID19_P12_B07GVPSRFSGSGSGTDFTLTISSLQPEDFATYY 108 COVID19_P24_H04GVPSRFSGSGSGTDFTLTISSLQPEDFATYY 109 COVID19_P23_G10GVPSRFSGSGSGTDFTLTISSLQPEDFATYY 110 COVID19_P24_A09GIPARFSGSGSGTEFTLTISSLQSEDFAVYY 111 COVID19_P11_D12GVPSRFSGSGSGTDFTLTISSLQPEDFATYY 112 COVID19_P24_A11GVPSRFSGSGSGTDFTLTISSLQPEDFATYY 113 COVID19_P24_C10GVPSRFSGSGSGTDFTLTISSLQPEDFATYY 114 COVID19_P11_D08GVPSRFSGSGSGTDFTLTISSLQPEDFATYY 115 COVID19_P24_E02GVPSRFSGSGSGTDFTLTISSLQPEDFATYY 116 COVID19_P23_H10GVPSRFSGSGSGTDFTLTISSLQPEDFATYY 117 COVID19_P24_G06GVPDRFSGSGSGTDFTLTISSLQAEDVAVYY 118 COVID19_P24_C01GVPSRFSGSGSGTDFTLTISSLQPEDFATYY 119 COVID19_P24_G09GVPSRFSGSGSGTDFTLTISSLQPEDFATYY 120 COVID19_P24_D08GVPSRFSGSGSGTDFTLTISSLQPEDFATYY 121 COVID19_P11_H07GVPSRFSGSGSGTDFTLTISSLQPEDFATYY 122 COVID19_P11_G03GVPSRFSGSGSGTDFTLTISSLQPEDFATYY 123 COVID19_P24_B09GVPSRFSGSGSGTDFTLTISSLQPEDFATYY 124 COVID19_P23_G12GVPSRFSGSGSGTDFTLTISSLQPEDFATYY 124

Representative FW-L4 Sequences

A SH antibody or antigen-binding fragment herein that selectively bindsto SARS-CoV-2 can comprise FW-L4 having an amino acid sequence that isat least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to any one of thefollowing sequences:

Clone ID FW-L4 SEQ ID NO: COVID19_P23_F10 GQGTKVEIKR 149 COVID19_P24_H06GQGTKVEIKR 150 COVID19_P24_F11 GGGTKVEIKR 151 COVID19_P23_G11 GQGTKLEIKR152 COVID19_P24_D09 GQGTKLEIKR 153 COVID19_P11_H02 GQGTKLEIKR 154COVID19_P24_C06 GQGTKLEIKR 155 COVID19_P12_B07 GGGTKVEIKR 156COVID19_P24_H04 GQGTKVEIKR 157 COVID19_P23_G10 GQGTKVEIKR 158COVID19_P24_A09 GGGTKVEIKR 159 COVID19_P11_D12 GQGTKLEIKR 160COVID19_P24_A11 GQGTKLEIKR 161 COVID19_P24_C10 GQGTKLEIKR 162COVID19_P11_D08 GQGTKLEIKR 163 COVID19_P24_E02 GQGTKVEIKR 164COVID19_P23_H10 GGGTKVEIKR 165 COVID19_P24_G06 GGGTKVEIKR 166COVID19_P24_C01 GQGTKVEIKR 167 COVID19_P24_G09 GQGTKVEIKR 168COVID19_P24_D08 GGGTKLEIKR 169 COVID19_P11_H07 GGGTKVEIKR 170COVID19_P11_G03 GPGTKVDIKR 171 COVID19_P24_B09 GPGTKVDIKR 172COVID19_P23_G12 GQGTKLEIKR 435

Representative FW-H1 Sequences

A SH antibody or antigen-binding fragment herein can comprise a VHframework (FW) 1 (FW-H1) having an amino acid sequence that is at least20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%,90%, 95%, 98%, 99%, or 100% identical to any one of the followingsequences:

SEQ ID Clone ID FW-H1 NO: COVID19_P23_F10 QVQLVQSGAEVKKPGASVKVSCKASG 173COVID19_P24_H06 EVQLLESGGGLVQPGGSLRLSCAASG 174 COVID19_P24_F11EVQLLESGGGLVQPGGSLRLSCAASG 175 COVID19_P23_G11QVQLVQSGAEVKKPGASVKVSCKASG 176 COVID19_P24_D09QVQLVQSGAEVKKPGASVKVSCKASG 177 COVID19_P11_H02QVQLVQSGAEVKKPGASVKVSCKASG 178 COVID19_P24_C06QVQLVQSGAEVKKPGASVKVSCKASG 179 COVID19_P12_B07QVQLVQSGAEVKKPGASVKVSCKASG 180 COVID19_P24_H04QVQLVQSGAEVKKPGASVKVSCKASG 181 COVID19_P23_G10QVQLVQSGAEVKKPGSSVKVSCKASG 182 COVID19_P24_A09QVQLVQSGAEVKKPGASVKVSCKASG 183 COVID19_P11_D12QVQLVQSGAEVKKPGASVKVSCKASG 184 COVID19_P24_A11QVQLVQSGAEVKKPGASVKVSCKASG 185 COVID19_P24_C10QVQLVQSGAEVKKPGASVKVSCKASG 186 COVID19_P11_D08QVQLVQSGAEVKKPGASVKVSCKASG 187 COVID19_P24_E02QVQLVQSGAEVKKPGASVKVSCKASG 188 COVID19_P23_H10QVQLVQSGAEVKKPGASVKVSCKASG 189 COVID19_P24_G06QVQLVQSGAEVKKPGASVKVSCKASG 190 COVID19_P24_C01QVQLVQSGAEVKKPGASVKVSCKASG 191 COVID19_P24_G09QVQLVQSGAEVKKPGASVKVSCKASG 192 COVID19_P24_D08QVQLVQSGAEVKKPGASVKVSCKASG 193 COVID19_P11_H07QVQLVQSGAEVKKPGASVKVSCKASG 194 COVID19_P11_G03QVQLVQSGAEVKKPGASVKVSCKASG 195 COVID19_P24_B09QVQLVQSGAEVKKPGSSVYVSCKASG 196 COVID19_P23_G12QVQLVQSGAEVKKPGASVKVSCKASG 194

Representative FW-H2 Sequences

A SH antibody or antigen-binding fragment herein that selectively bindsto SARS-CoV-2 can comprise a FW-112 having an amino acid sequence thatis at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to any one of thefollowing sequences:

Clone ID FW-H2 SEQ ID NO: COVID19_P23_F10 WVRQAPGQGLEWM 221COVID19_P24_H06 WVRQAPGKGLEWV 222 COVID19_P24_F11 WVRQAPGKGLEYV 223COVID19_P23_G11 WVRQAPGQGLEWM 224 COVID19_P24_D09 WVRQAPGQGLEWM 225COVID19_P11_H02 WVRQAPGQGLEWM 226 COVID19_P24_C06 WVRQAPGQGLEWM 227COVID19_P12_B07 WVRQAPGQGLEWM 228 COVID19_P24_H04 WVRQAPGQGLEWM 229COVID19_P23_G10 WVRQAPGQGLEWM 230 COVID19_P24_A09 WVRQAPGQGLEWM 231COVID19_P11_D12 WVRQAPGQGLEWM 232 COVID19_P24_A11 WVRQAPGQGLEWM 233COVID19_P24_C10 WVRQAPGQGLEWM 234 COVID19_P11_D08 WVRQAPGQGLEWM 235COVID19_P24_E02 WVRQAPGQGLEWM 236 COVID19_P23_H10 WVRQAPGQGLEWM 237COVID19_P24_G06 WVRQAPGQGLEWM 238 COVID19_P24_C01 WVRQAPGQGLEWM 239COVID19_P24_G09 WVRQAPGQGLEWM 240 COVID19_P24_D08 WVRQAPGQGLEWM 241COVID19_P11_H07 WVRQAPGQGLEWM 242 COVID19_P11_G03 WVRQAPGQGLEWM 243COVID19_P24_B09 WVRQAPGQGLEWM 244 COVID19_P23_G12 WVRQAPGQGLEWM 244

Representative FW-H3 Sequences

A SH antibody or antigen-binding fragment herein that selectively bindsto SARS-CoV-2 can comprise a FW-113 having an amino acid sequence thatis at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to any one of thefollowing sequences:

Clone ID FW-H3 SEQ ID NO: COVID19_P23_F10QKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYY 269 COVID19_P24_H06DSVKGRFTISRDNAKNSLYLRMNSLRSEDTAVYY 270 COVID19_P24_F11DSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYY 271 COVID19_P23_G11QKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYY 272 COVID19_P24_D09QKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYY 273 COVID19_P11_H02LKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYY 274 COVID19_P24_C06QKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYY 275 COVID19_P12_B07HKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYY 276 COVID19_P24_H04QKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYY 277 COVID19_P23_G10QKFQGRVTITADESTSTAYMELSSLRSEDTAVYY 278 COVID19_P24_A09HSFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYY 279 COVID19_P11_D12QKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYY 280 COVID19_P24_A11QKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYY 281 COVID19_P24_C10QKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYY 282 COVID19_P11_D08QKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYY 283 COVID19_P24_E02QKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYY 284 COVID19_P23_H10QEFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYY 285 COVID19_P24_G06QKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYY 286 COVID19_P24_C01QKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYY 287 COVID19_P24_G09QKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYY 288 COVID19_P24_D08QKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYY 289 COVID19_P11_H07QKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYY 290 COVID19_P11_G03QKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYY 291 COVID19_P24_B09QKFQGRVTITADKSTSTAYMELSSLRSEDTAVYY 292 COVID19_P23_G12QKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYY 291

Representative FW-H4 Sequences

A SH antibody or antigen-binding fragment herein that selectively bindsto SARS-CoV-2 can comprise a FW-114 having an amino acid sequence thatis at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%,80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to any one of thefollowing sequences:

Clone ID FW-H4 SEQ ID NO: COVID19_P23_F10 GQGTLVNVSS 317 COVID19_P24_H06GKGTTVTVSS 318 COVID19_P24_F11 GQGTLVTVSS 319 COVID19_P23_G11 GKGTTVTVSS320 COVID19_P24_D09 GQGTTVTVSS 321 COVID19_P11_H02 GQGTLVTVSS 322COVID19_P24_C06 GQGTMVTVSS 323 COVID19_P12_B07 GQGTLVTVSS 324COVID19_P24_H04 GQGTMVTVSS 325 COVID19_P23_G10 GQGTLVTVSS 326COVID19_P24_A09 GRGTLVTVSS 327 COVID19_P11_D12 GQGTTVTVSS 328COVID19_P24_A11 GQGTTVTVSS 329 COVID19_P24_C10 GQGTTVTVSS 330COVID19_P11_D08 GQGTTVTVSS 331 COVID19_P24_E02 GQGTLVTVSS 332COVID19_P23_H10 GQGTLVTVSS 333 COVID19_P24_G06 GQGTMVTVSS 334COVID19_P24_C01 GQGTMVTVSS 335 COVID19_P24_G09 GQGTMVTVSS 336COVID19_P24_D08 GQGTTVTVSS 337 COVID19_P11_H07 GQGTMVTVSS 338COVID19_P11_G03 GQGTTVTVSS 339 COVID19_P24_B09 GQGTLVTVSS 340COVID19_P23_G12 GQGTMVTVSS 338

Representative SH VH and VL Sequences that Bind to SARS-CoV-2

A SH antibody or antigen-binding fragment herein that selectively bindsto SARS-CoV-2 can comprise an VH amino acid sequence that is at least70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to any one ofthe following sequences:

SEQ ID Clone ID VH NO: COVID19_QVQLVQSGAEVKKPGASVKVSCKASGDTFSNYGISWVRQAPGQGLEWM 341 P23_F10GWMNPNSGGTNYAQKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCA IGTTVVTPFGYWGQGTLVNVSSCOVID19_ EVQLLESGGGLVQPGGSLRLSCAASGFSFSNYDMHWVRQAPGKGLEWVA 342 P24_H06VISYDGGFKLYADSVKGRFTISRDNAKNSLYLRMNSLRSEDTAVYYCARGQVRGSGPQVVVMDVWGKGTTVTVSS COVID19_EVQLLESGGGLVQPGGSLRLSCAASGFTFSGSAMHWVRQAPGKGLEYVS 343 P24_F11AISRNGGTTYYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYYCAKD GTLITTTLDYWGQGTLVTVSSCOVID19_ QVQLVQSGAEVKKPGASVKVSCKASGGTFRSTAISWVRQAPGQGLEWMG 344 P23_G11WMNPNSGNTGYAQKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCARAGYSSSSGYYYYGMDVWGKGTTVTVSS COVID19_QVQLVQSGAEVKKPGASVKVSCKASGGTFSSYAISWVRQAPGQGLEWMG 345 P24_D09IVNPSSGSTTYAQKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCARVRGSAAIAMMDVWGQGTTVTVSS COVID19_QVQLVQSGAEVKKPGASVKVSCKASGGTFTSYHMHWVRQAPGQGLEWM 346 P11_H02GWMNPNSGNTGYALKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCASFERFGELVPETFDYWGQGTLVTVSS COVID19_QVQLVQSGAEVKKPGASVKVSCKASGYIFTSYPIHWVRQAPGQGLEWMG 347 P24_C06WMNPNSGNTGYAQKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCARDRGSYDTDAFDIWGQGTMVTVSS COVID19_QVQLVQSGAEVKKPGASVKVSCKASGYTFINYDINWVRQAPGQGLEWM 348 P12_B07GVINPSAGSTSYAHKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCASAHSSSWYSDWFDPWGQGTLVTVSS COVID19_QVQLVQSGAEVKKPGASVKVSCKASGYTFTDYHMHWVRQAPGQGLEW 349 P24_H04MGWMNPNSGNTSYAQKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCAGMGMGRDGYNSRAFDIWGQGTMVTVSS COVID19_QVQLVQSGAEVKKPGSSVKVSCKASGYTFTDYYIQWVRQAPGQGLEWM 350 P23_G10GWINPNSGGPNYAQKFQGRVTITADESTSTAYMELSSLRSEDTAVYYCARVDYGDYGRLEDYWGQGTLVTVSS COVID19_QVQLVQSGAEVKKPGASVKVSCKASGYTFTDYYMQWVRQAPGQGLEW 351 P24_A09MGWIDPHSGATNYAHSFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCARLEGGSYWTGYFDLWGRGTLVTVSS COVID19_QVQLVQSGAEVKKPGASVKVSCKASGYTFTENEMHWVRQAPGQGLEWM 352 P11_D12GIINPSGGSTSYAQKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCAKTRYGGNSRSRYYYYGMDVWGQGTTVTVSS COVID19_QVQLVQSGAEVKKPGASVKVSCKASGYTFTENEMHWVRQAPGQGLEWM 353 P24_A11GIINPSGGSTSYAQKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCARDLMDIVVVPWLGGMDVWGQGTTVTVSS COVID19_QVQLVQSGAEVKKPGASVKVSCKASGYTFTENEMHWVRQAPGQGLEWM 354 P24_C10GIINPSGGSTSYAQKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCARDSGVDTATLRYYYYGMDVWGQGTTVTVSS COVID19_QVQLVQSGAEVKKPGASVKVSCKASGYTFTENEMHWVRQAPGQGLEWM 355 P11_D08GIINPSGGSTSYAQKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCARDSGVDTATLRYYYYGMDVWGQGTTVTVSS COVID19_QVQLVQSGAEVKKPGASVKVSCKASGYTFTGNYIHWVRQAPGQGLEWM 356 P24_E02GWMNPNSGNTGYAQKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCAKDVQNYYGSGSSFDYWGQGTLVTVSS COVID19_QVQLVQSGAEVKKPGASVKVSCKASGYTFTGSYAISWVRQAPGQGLEWM 357 P23_H10GWINPKTGDTNYAQEFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCA RGSSGYYFGWGQGTLVTVSSCOVID19_ QVQLVQSGAEVKKPGASVKVSCKASGYTFTNYGISWVRQAPGQGLEWM 358 P24_G06GWISARNGNTNYAQKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCTTDPVLEWFGYSIWGQGTMVTVSS COVID19_QVQLVQSGAEVKKPGASVKVSCKASGYTFTRYYIHWVRQAPGQGLEWM 359 P24_C01GIINPSGGSTTYAQKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCAKGAPHDYIWGSYRPDAFDIWGQGTMVTVSS COVID19_QVQLVQSGAEVKKPGASVKVSCKASGYTFTRYYIHWVRQAPGQGLEWM 360 P24_G09GIINPSGGSTTYAQKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCAKGAPHDYIWGSYRPDAFDIWGQGTMVTVSS COVID19_QVQLVQSGAEVKKPGASVKVSCKASGYTFTSYDINWVRQAPGQGLEWM 361 P24_D08GIIDPSGGSTSYAQKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCATV TPGYGMDVWGQGTTVTVSSCOVID19_ QVQLVQSGAEVKKPGASVKVSCKASGYTFTSYDINWVRQAPGQGLEWM 362 P11_H07GWMNSNSGSTGYAQKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCA RGWMAYDAFDIWGQGTMVTVSSCOVID19_ QVQLVQSGAEVKKPGASVKVSCKASGYTFTSYEINWVRQAPGQGLEWM 363 P11_G03GIINPSDGSSTYAQKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCARDRGYSYDHDQIYYYYGMDVWGQGTTVTVSS COVID19_QVQLVQSGAEVKKPGSSVYVSCKASGYTFTSYGISWVRQAPGQGLEWMG 364 P24_B09GIIPMFGTTNYAQKFQGRVTITADKSTSTAYMELSSLRSEDTAVYYCARDR GDTIDYWGQGTLVTVSSCOVID19_ QVQLVQSGAEVKKPGASVKVSCKASGYIFTSYPIHWVRQAPGQGLEWMG 436 P23_G12WMNPNSGNTGYAQKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCARDRGSYDTDAFDIWGQGTMVTVSS

A SH antibody or antigen-binding fragment herein that selectively bindsto SARS-CoV-2 can comprise an VL amino acid sequence that is at least70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% identical to any one ofthe following sequences

SEQ ID CloneID VL NO: COVID19_EIVMTQSPATLSVSPGERATLSCRASESVSSRYLAWYQQKPGQAPRLLIYG 365 P23_F10ASTRATGIPARFSGSGSGTEFTLTISSLQSEDFAVYYCQQGYKNPPTFGQGT KVEIKR COVID19_DIQMTQSPSSLSASVGDRVTITCQASQGIRNDLGWYQQKPGKAPKLLIYDA 366 P24_H06SRLQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQYYSTPPLTFGQGT KVEIKR COVID19_DIQMTQSPSSLSASVGDRVTITCRASQSIGYYLNWYQQKPGKAPKLLIYAA 367 P24_F11SSLQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQSYTTPLTFGGGTK VEIKR COVID19_DIQMTQSPSSLSASVGDRVTITCRASQGISNNLNWYQQKPGKAPKLLIYAA 368 P23__G11SSLQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQYDTFPLTFGQZTK VEIKR COVID19_DIQMTQSPSSLSASVGDRVTITCRASQDIRNELGWYQQKPGKAPKLLIYAA 369 P24_D09SSLQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQSYSTPPWTFGQGT KLEIKR COVID19_DIQMTQSPSSLSASVGDRVTITCRASQGIRNDLAWYQQKPGKAPKLLIYAA 370 P11_H02SSLQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQSYSTPPTFGQGTKL EIKR COVID19_DIQMTQSPSSLSASVGDRVTITCRASQDISNYLNWYQQKPGKAPKLLIYAA 371 P24_C06SNLQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQANSFPSTFGQGTK LEIKR COVID19_DIQMTQSPSSLSASVGDRVTITCRASQSISSYLNWYQQKPGKAPKLLIYAAS 372 P12_B07SLQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQSYSTPLTFGGGTKV EIKR COVID19_DIQMTQSPSSLSASVGDRVTITCRASQSISTYLNWYQQKPGKAPKLLIYAAS 373 P24_H04TLQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQSYSMPLTFGQGTKV EIKR COVID19_DIQMTQSPSSLSASVGDRVTITCRASQSIYSWLAWYQQKPGKAPKLLIYDA 374 P23_G10SSLESGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQLNSYPYTFGQGTK VEIKR COVID19_EIVMTQSPATLSVSPGERATLSCRASQSVSSNYLAWYQQKPGQAPRLLIYA 375 P24_A09VSSRATGIPARFSGSGSGTEFTLTISSLQSEDFAVYYCQQYGSSPLTFGGGT KVEIKR COVID19_DIQMTQSPSSLSASVGDRVTITCRASQHISSYLNWYQQKPGKAPKLLIYAA 376 P11_D12SALQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQGYGTPYTFGZZTK VEIKR COVID19_DIQMTQSPSSLSASVGDRVTITCRASQAITNYLAWYQQKPGKAPKLLIYAA 377 P24_A11SSLQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQYYSYPPTFGQGTK LEIKR COVID19_DIQMTQSPSSLSASVGDRVTITCQASQDISKYLNWYQQKPGKAPKLLIYGA 378 P24_C10STLSDGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQGYSTPYSFGQGTK LEIKR COVID19_DIQMTQSPSSLSASVGDRVTITCQASQDISKYLNWYQQKPGKAPKLLIYGA 379 P11_D08STLSDGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQGYSTPYSFGZGTK LEIKR COVID19_DIQMTQSPSSLSASVGDRVTITCRASQGIRNYLAWYQQKPGKAPKLLIYAA 380 P24_E02STLQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQSYSPPLTFGQGTK VEIKR COVID19_DIQMTQSPSSLSASVGDRVTITCRASQSISSYLNWYQQKPGKAPKLLIYAAS 381 P23_H10RLQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQSYSTPLTFGGGTKV EIKR COVID19_DIVMTQSPDSLAVSLGERATINCKSSQSVFSSSNNKNYLAWYQQKPGQPPK 382 P24_G06LLIYWASTRESGVPDRFSGSGSGTDFTLTISSLQAEDVAVYYCQQYYSTPL TFGGZTKVEIKRCOVID19_ DIQMTQSPSSLSASVGDRVTITCRASENIDSWLAWYQQKPGKAPKLLIYEA 383 P24_C01STLESGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCHQYLSSPETFGQGTK VEIKR COVID19_DIQMTQSPSSLSASVGDRVTITCRASENIDSWLAWYQQKPGKAPKLLIYEA 384 P24_G09STLESGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCHQYLSSPETFGQGTK VEIKR COVID19_DIQMTQSPSSLSASVGDRVTITCRASQTIYSYLNWYQQKPGKAPKLLIYDA 385 P24_D08SNLETGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQAISFPLTFGGGTKL EIKR COVID19_DIQMTQSPSSLSASVGDRVTITCQASQSIYNYLNWYQQKPGKAPKLLIYDA 386 P11_H07SNLETGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQAISFPLTFGGGTKV EIKR COVID19_DIQMTQSPSSLSASVGDRVTITCRVSQGISSYLNWYQQKPGKAPKLLIYAA 387 P11_G03SILQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQGYSTPFTFGPGTKV DIKR COVID19_DIQMTQSPSSLSASVGDRVTITCRASQGISNNLNWYQQKPGKAPKLLIYAA 388 P24_B09SSLESGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQGNGFPLTFGPGTK VDIKR COVID19_DIQMTQSPSSLSASVGDRVTITCRASQDISNYLNWYQQKPGKAPKLLIYAA 437 P23_G12SNLQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQANSFPSTFGQGTK LEIKR

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 341 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 365.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 342 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 366.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 343 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 367.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 344 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 368.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 345 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 369.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 346 and an VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 370.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 347 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 371.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 348 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 372.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 349 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 373.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 350 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 374.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 351 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 375.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 352 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 376.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 353 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 377.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 354 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 378.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 355 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 379.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 356 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 380.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 357 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 381.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 358 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 382.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 359 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 383.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 360 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 384.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 361 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 385.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 362 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 386.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 363 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 387.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 364 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 388.

In one instance, a SH antibody or antigen-binding fragment, herein thatselectively binds to SARS-Cov-2 can comprise a VH having an amino acidsequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or100% identical to SEQ ID NO: 436 and a VL having an amino acid sequencethat is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100%identical to SEQ ID NO: 437.

Modified Antibodies

The present disclosure provides for modified antibodies. Modifiedantibodies can comprise antibodies which have one or more modificationswhich can enhance their activity, binding, specificity, selectivity, oranother feature. In one aspect, the present disclosure provides formodified antibodies (which can be heteromultimers) that comprise ananti-SARS-Cov-2 antibody as herein. Reference to a modified antibodyherein also refers to a modified antigen-binding fragment.

A modified antibody can comprise a bispecific modified antibody, atrispecific modified antibody or antigen-binding fragment, or atetraspecific modified antibody or antigen-binding fragment. Abispecific modified antibody can be able to specifically bind to 2targets. In some cases, one of the targets a bispecific modifiedantibody can specifically bind to can be a SARS-CoV-2. A trispecificmodified antibody can be able to specifically bind to 3 targets. In somecases, one of the targets a trispecific modified antibody canspecifically bind to can be a SARS-CoV-2. A tetraspecific modifiedantibody can be able to specifically bind to 4 targets. In some cases,one of the targets a tetraspecific modified antibody can specificallybind to can be a SARS-CoV-2.

A modified antibody can comprise a human modified antibody. Alsoincluded herein are amino acid sequence variants of the modifiedantibody which can be prepared by introducing appropriate nucleotidechanges into the modified antibody DNA, or by synthesis of the desiredmodified antibody polypeptide. Such variants include, for example,deletions from, or insertions or substitutions of, residues within theamino acid sequences of the first and second polypeptides forming themodified antibody. Any combination of deletion, insertion, andsubstitution is made to arrive at the final construct, provided that thefinal construct possesses the desired antigen-binding characteristics.The amino acid changes also may alter post-translational processes ofthe modified antibody, such as changing the number or position ofglycosylation sites.

“Alanine scanning mutagenesis” can be a useful method for identificationof certain residues or regions of the modified antibody polypeptidesthat might be preferred locations for mutagenesis. Here, a residue orgroup of target residues are identified (e.g., charged residues such asArg, Asp, His, Lys, and Glu) and replaced by a neutral or negativelycharged amino acid (for example, alanine or polyalanine) to affect theinteraction of the amino acids with the surrounding aqueous environmentin or outside the cell. Those domains demonstrating functionalsensitivity to the substitutions then are refined by introducing furtheror other variants at or for the sites of substitution. Thus, while thesite for introducing an amino acid sequence variation is predetermined,the nature of the mutation per se need not be predetermined.

Normally the mutations can involve conservative amino acid replacementsin non-functional regions of the modified antibody. Exemplary mutationsare shown below.

Original Preferred Residue Exemplary Substitutions Substitutions Ala (A)Val; Leu; Ile Val Arg (R) Lys; Gln; Asn Lys Asn (N) Gln; His; Lys; ArgGln Asp (D) Glu Glu Cys (C) Ser Ser Gln (Q) Asn Asn Glu (E) Asp Asp Gly(G) Pro; Ala Ala His (H) Asn; Gln; Lys; Arg Arg Ile (I) Leu; Val; Met;Ala; Phe; Norleucine Leu Leu (L) Norleucine; Ile; Val; Met; Ala; Phe IleLys (K) Arg; Gln; Asn Arg Met (M) Leu; Phe; Ile Leu Phe (F) Leu; Val;Ile; Ala; Tyr Leu Pro (P) Ala Ala Ser (S) Thr Thr Thr (T) Ser Ser Trp(W) Tyr; Phe Tyr Tyr (Y) Trp; Phe; Thr; Ser Phe Val (V) Ile; Leu; Met;Phe; Ala; Norleucine Leu

Covalent modifications of antibody, antigen-binding fragment, ormodified antibody polypeptides are included within the scope of thisdisclosure. Covalent modifications of the modified antibody can beintroduced into the molecule by reacting targeted amino acid residues ofthe modified antibody or fragments thereof with an organic derivatizingagent that can be capable of reacting with selected side chains or theN- or C-terminal residues. Another type of covalent modification of themodified antibody polypeptide can comprise altering the nativeglycosylation pattern of the polypeptide. Herein, “altering” can meandeleting one or more carbohydrate moieties found in the originalmodified antibody, and/or adding one or more glycosylation sites thatare not present in the original modified antibody. Addition ofglycosylation sites to the modified antibody polypeptide can beaccomplished by altering the amino acid sequence such that it containsone or more N-linked glycosylation sites. The alteration may also bemade by the addition of, or substitution by, one or more serine orthreonine residues to the original modified antibody sequence (forO-linked glycosylation sites). For ease, the modified antibody aminoacid sequence can be altered through changes at the DNA level,particularly by mutating the DNA encoding the modified antibodypolypeptide at preselected bases such that codons are generated thatwill translate into the desired amino acids. Another means of increasingthe number of carbohydrate moieties on the modified antibody polypeptideis by chemical or enzymatic coupling of glycosides to the polypeptide.Removal of carbohydrate moieties present on the modified antibody can beaccomplished chemically or enzymatically.

Another type of covalent modification of modified antibody compriseslinking the modified antibody polypeptide to one of a variety ofnon-proteinaceous polymers, e.g., polyethylene glycol, polypropyleneglycol, or polyoxyalkylenes.

Methods for complexing binding agents or the antibody or antigen-bindingfragments thereof herein with another agent are known in the art. Suchmethods may utilize one of several available heterobifunctional reagentsused for coupling or linking molecules.

In one instance, Fc portions of antibodies can be modified to increasehalf-life of the molecule in the circulation in blood when administeredto a subject.

Additionally, antibodies may be produced or expressed so that they donot contain fucose on their complex N-glycoside-linked sugar chains toincrease effector functions. Similarly, antibodies can be attached attheir C-terminal end to all or part of an immunoglobulin heavy chainderived from any antibody isotype, e.g., IgG, IgA, IgE, IgD, and IgM andany of the isotype subclasses, e.g., IgG1, IgG2b, IgG2a, IgG3, and IgG4.

Glycosylation of immunoglobulins has been shown to have significanteffects on their effector functions, structural stability, and rate ofsecretion from antibody-producing cells. Antibodies and antigen-bindingfragments herein may be glycosylated. Glycosylation at a variable domainframework residue can alter the binding interaction of the antibody withantigen. The present disclosure includes criteria by which a limitednumber of amino acids in the framework or CDRs of an immunoglobulinchain can be chosen to be mutated (e.g., by substitution, deletion,and/or addition of residues) in order to increase the affinity of anantibody.

Linkers for conjugating antibodies to other moieties are within thescope of the present disclosure. Associations (binding) betweenantibodies and labels include, but are not limited to, covalent andnon-covalent interactions, chemical conjugation, as well as recombinanttechniques.

Antibodies, or antigen-binding fragments thereof, can be modified forvarious purposes such as, for example, by addition of polyethyleneglycol (PEG). PEG modification (PEGylation) can lead to one or more ofimproved circulation time, improved solubility, improved resistance toproteolysis, reduced antigenicity and immunogenicity, improvedbioavailability, reduced toxicity, improved stability, and easierformulation.

An antibody or antigen-binding fragment can be conjugated to, orrecombinantly engineered with, an affinity tag (e.g., a purificationtag). Affinity tags such as, for example, His6 tags(His-His-His-His-His-His) (SEQ ID NO: 442) have been described.

Since it is often difficult to predict in advance the characteristics ofa variant modified antibody, it will be appreciated that some screeningof the recovered variants may be needed to select an optimal variant.Exemplary methods of screening the recovered variants are describedbelow in the Examples.

Methods of Expressing Antibodies

Also provided herein are methods of making any of these antibodies orpolypeptides. The polypeptides can be produced by proteolytic or otherdegradation of the antibodies, by recombinant methods (i.e., single orfusion polypeptides) as described above, or by chemical synthesis.Polypeptides of the antibodies, especially shorter polypeptides up toabout 50 amino acids, can be made by chemical synthesis. Methods ofchemical synthesis are commercially available. For example, an antibodycould be produced by an automated polypeptide synthesizer employing asolid phase method.

Antibodies may be made recombinantly by first isolating the antibodiesand antibody producing cells from host animals, obtaining the genesequence, and using the gene sequence to express the antibodyrecombinantly in host cells (e.g., CHO cells). Another method which maybe employed is to express the antibody sequence in plants (e.g.,tobacco) or transgenic milk. Methods for expressing antibodiesrecombinantly in plants or milk have been disclosed. Methods for makingderivatives of antibodies, e.g., single chain, etc. are also within thescope of the present disclosure.

As used herein, “host cell” includes an individual cell or cell culturethat can be or has been a recipient for vector(s) for incorporation ofpolynucleotide inserts. Host cells include progeny of a single hostcell, and the progeny may not necessarily be completely identical (inmorphology or in genomic DNA complement) to the original parent cell dueto natural, accidental, or deliberate mutation. A host cell includescells transfected with a polynucleotide(s) of this disclosure.

DNA encoding an antibody may be readily isolated and sequenced usingconventional procedures (e.g., by using oligonucleotide probes that arecapable of binding specifically to genes encoding the heavy and lightchains of the monoclonal antibodies). Hybridoma cells may serve as asource of such DNA. Once isolated, the DNA may be placed into one ormore expression vectors (such as expression vectors disclosed in PCTPublication No. WO 87/04462), which are then transfected into host cellssuch as E. coli cells, simian COS cells, Chinese hamster ovary (CHO)cells, or myeloma cells that do not otherwise produce immunoglobulinprotein, to obtain the synthesis of monoclonal antibodies in therecombinant host cells. The DNA also may be modified, for example, bysubstituting the coding sequence for human heavy and light chainconstant domains in place of the homologous murine sequences, or bycovalently joining to the immunoglobulin coding sequence all or part ofthe coding sequence for a non-immunoglobulin polypeptide. In thatmanner, “chimeric” or “hybrid” antibodies are prepared that have thebinding specificity of an antibody herein.

Contemplated herein are vectors that encode the one or more antibodiesor antigen-binding fragments herein. As used herein, “vector” means aconstruct, which is capable of delivering, and possibly expressing, oneor more gene(s) or sequence(s) of interest in a host cell. Examples ofvectors include, but are not limited to, viral vectors; naked DNA or RNAexpression vectors; plasmid, cosmid, or phage vectors; DNA or RNAexpression vectors associated with cationic condensing agents; DNA orRNA expression vectors encapsulated in liposomes; and certain eukaryoticcells, such as producer cells.

As used herein, “expression control sequence” means a nucleic acidsequence that directs transcription of a nucleic acid. An expressioncontrol sequence can be a promoter, such as a constitutive or aninducible promoter, or an enhancer. The expression control sequence isoperably linked to the nucleic acid sequence to be transcribed. Anexpression vector can be used to direct expression of an antibody.Expression vectors can be administered to obtain expression of anexogenous protein in vivo.

For high level production, a widely used mammalian expression system isone which utilizes Lonza's GS Gene Expression System™. This system usesa viral promoter and selection via glutamine metabolism to providedevelopment of high-yielding and stable mammalian cell lines.

For alternative high-level production, a widely used mammalianexpression system is one which utilizes gene amplification bydihydrofolate reductase deficient (“dhfr”) Chinese hamster ovary cells.The system is based upon the dihydrofolate reductase “dhfr” gene, whichencodes the DHFR enzyme, which catalyzes conversion of dihydrofolate totetrahydrofolate. In order to achieve high production, dhfr-CHO cellsare transfected with an expression vector containing a functional DHFRgene, together with a gene that encodes a desired protein. In this case,the desired protein is recombinant antibody heavy chain and/or lightchain.

By increasing the amount of the competitive DHFR inhibitor methotrexate(MTX), the recombinant cells develop resistance by amplifying the dhfrgene. In standard cases, the amplification unit employed is much largerthan the size of the dhfr gene, and as a result the antibody heavy chainis co-amplified.

When large scale production of the protein, such as the antibody chain,is desired, both the expression level and the stability of the cellsbeing employed are taken into account.

The present application provides one or more isolated polynucleotides(nucleic acids) encoding an antibody or an antigen-binding fragmentherein, vectors containing such polynucleotides, and host cells andexpression systems for transcribing and translating such polynucleotidesinto polypeptides.

The present application also provides constructs in the form ofplasmids, vectors, transcription or expression cassettes which compriseat least one polynucleotide as above.

The present application also provides a recombinant host cell whichcomprises one or more constructs as above. A nucleic acid encoding anyantibody herein forms an aspect of the present application, as does amethod of production of the antibody, which method comprises expressionfrom encoding nucleic acid therefrom. Expression can be achieved byculturing under appropriate conditions recombinant host cells containingthe nucleic acid. Following production by expression, an antibody or aportion thereof can be isolated and/or purified using any suitabletechnique, then used as appropriate. Systems for cloning and expressionof a polypeptide in a variety of different host cells are contemplatedfor use herein.

A further aspect provides a host cell containing nucleic acid asdisclosed herein using any suitable method. A still further aspectprovides a method comprising introducing such nucleic acid into a hostcell. The introduction can be followed by causing or allowing expressionfrom the nucleic acid, e.g., by culturing host cells under conditionsfor expression of the gene.

One or more polynucleotides encoding an antibody or an antigen-bindingfragment can be prepared recombinantly/synthetically in addition to, orrather than, cloned. In a further embodiment, the full DNA sequence ofthe recombinant DNA molecule or cloned gene(s) of an antibody orantigen-binding fragment herein can be operatively linked to anexpression control sequence which can be introduced into an appropriatehost using any suitable method.

Nucleic acid sequences can be expressed by operatively linking them toan expression control sequence in an appropriate expression vector andemploying that expression vector to transform an appropriate host cell.Any of a wide variety of expression control sequences—sequences thatcontrol the expression of a nucleic acid sequence operatively linked toit—can be used in these vectors to express the nucleic acid sequences.

A wide variety of host/expression vector combinations can be employed inexpressing the nucleic acid sequences of this disclosure. It will beunderstood that not all vectors, expression control sequences, and hostswill function equally well to express the nucleic acid sequences.Neither will all hosts function equally well with the same expressionsystem. In some embodiments, in selecting a vector, the host isconsidered such that the vector can function in it. The vector's copynumber, the ability to control that copy number, and the expression ofany other proteins encoded by the vector, such as antibiotic markers,may also be considered. In certain embodiments, in selecting a vector,the host is considered such that the vector functions in it. Thevector's copy number, the ability to control that copy number, and theexpression of any other proteins encoded by the vector, such asantibiotic markers, can also be considered.

The present application also provides a method which comprises using aconstruct as stated above in an expression system in order to expressthe antibodies (or portions thereof) as above. Considering these andother factors, a variety of vector/expression control sequence/hostcombinations can be constructed that can express the nucleic acidsequences on fermentation or in large scale animal culture.

Simultaneous incorporation of the antibody (or portion thereof)-encodingnucleic acids and the selected amino acid position changes can beaccomplished by a variety of suitable methods including, for example,recombinant and chemical synthesis.

Provided herein are methods of expressing an antibody or antigen-bindingfragment antigen-binding that can selectively bind to SARS-Cov-2 in asubject comprising administering to the subject a composition comprisingone or more polynucleotides (e.g., mRNA) encoding the antibody orantigen-binding fragment.

In some cases, administering the one or more polynucleotides to thesubject can comprise enteral, gastroenteral, oral, transdermal,epicutaneous, intradermal, subcutaneous, nasal administration,intravenous, intraperitoneal, intraarterial, intramuscular, intraosseousinfusion, transmucosal, insufflation, or sublingual administration. Insome cases, a polynucleotide can be administered via more than oneroute.

Antibodies or antigen-binding fragments can be synthesized in thesubject based at least in part on the polynucleotide encoding theantibody or antigen-binding fragment. For example, a polynucleotide canenter a cell of the subject, and the antibody or antigen-bindingfragment can be synthesized at least in part by using the subject'scellular transcription and/or translation machinery. In some cases, forexample where the polynucleotide is an mRNA molecule, the antibody orantigen-binding fragment can be synthesized at least in part by usingthe subject's cellular translation machinery (e.g., ribosomes, tRNA,etc.). In some cases, antibody or antigen-binding fragments can betransported from a cell to the plasma of the subject after translation.

Compositions

Compositions comprising a SH antibody or antigen-binding fragment hereinmay be prepared for storage by mixing an antibody or antigen-bindingfragment having the desired degree of purity with optionalpharmaceutically acceptable carriers, excipients or stabilizers(Remington, The Science and Practice of Pharmacy 20th Ed. MackPublishing (2000)), in the form of lyophilized formulations or aqueoussolutions.

As used herein, “pharmaceutically acceptable carrier” or “pharmaceuticalacceptable excipient” includes any material which, when combined with anactive ingredient, allows the ingredient to retain biological activityand is non-reactive with the subject's immune system. Examples include,but are not limited to, any of the standard pharmaceutical carriers suchas a phosphate buffered saline solution, water, emulsions such asoil/water emulsion, and various types of wetting agents. Preferreddiluents for aerosol or parenteral administration are phosphate bufferedsaline or normal (0.9%) saline. Compositions comprising such carriersare formulated by well-known conventional methods (see, for example,Remington's Pharmaceutical Sciences, 18th edition, A. Gennaro, Ed., MackPublishing Co., Easton, Pa., 1990; and Remington, The Science andPractice of Pharmacy 20th Ed. Mack Publishing, 2000).

Acceptable carriers, excipients, or stabilizers are nontoxic torecipients at the dosages and concentrations employed, and may comprisebuffers such as phosphate, citrate, and other organic acids; salts suchas sodium chloride; antioxidants including ascorbic acid and methionine;preservatives (such as octadecyldimethylbenzyl ammonium chloride;hexamethonium chloride; benzalkonium chloride, benzethonium chloride;phenol, butyl or benzyl alcohol; alkyl parabens, such as methyl orpropyl paraben; catechol; resorcinol; cyclohexanol; 3-pentanol; andm-cresol); low molecular weight (less than about 10 residues)polypeptides; proteins, such as serum albumin, gelatin, orimmunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone;amino acids such as glycine, glutamine, asparagine, histidine, arginine,or lysine; monosaccharides, disaccharides, and other carbohydratesincluding glucose, mannose, or dextrins; chelating agents such as EDTA;sugars such as sucrose, mannitol, trehalose or sorbitol; salt-formingcounter-ions such as sodium; metal complexes (e.g., Zn-proteincomplexes); and/or non-ionic surfactants such as TWEEN™, PLURONICS™ orpolyethylene glycol (PEG).

The compositions to be used for in vivo administration may besterilized. This may be accomplished by, for example, filtration throughsterile filtration membranes, or any other art-recognized method forsterilization. Antibody compositions are generally placed into acontainer having a sterile access port, for example, an intravenoussolution bag or vial having a stopper pierceable by a hypodermicinjection needle. Other methods for sterilization and filtration areknown in the art and are contemplated herein.

In one embodiment of the present invention, the compositions areformulated to be free of pyrogens such that they are acceptable foradministration to a subject.

The compositions according to the present invention may be in unitdosage forms such as solutions or suspensions, tablets, pills, capsules,powders, granules, or suppositories, etc., for intravenous, oral,parenteral or rectal administration, or administration by inhalation orinsufflation.

The phrase “pharmaceutically acceptable” refers to molecular entitiesand compositions that are physiologically tolerable and do not typicallyproduce an allergic or similar untoward reaction, such as gastric upset,dizziness and the like, when administered to a subject.

In some instances, an antibody or antigen-binding fragment can be boundto one or more carriers. Carriers can be active and/or inert. Examplesof well-known carriers include polypropylene, polystyrene, polyethylene,dextran, nylon, amylases, glass, natural and modified celluloses,polyacrylamides, agaroses and magnetite. The nature of the carrier canbe either soluble or insoluble for purposes of the invention. Thoseskilled in the art will know of other suitable carriers for bindingantibodies, or will be able to ascertain such, using routineexperimentation.

One embodiment contemplates the use of the antibodies andantigen-binding fragments to manufacture a medicament for treating acondition, disease or disorder described herein. Medicaments can beformulated based on the physical characteristics of the subject needingtreatment, and can be formulated in single or multiple formulationsbased on the stage of the condition, disease or disorder. Medicamentscan be packaged in a suitable package with appropriate labels for thedistribution to hospitals and clinics wherein the label is for theindication of treating a subject having a disease described herein.Medicaments can be packaged as a single or multiple units. Instructionsfor the dosage and administration of the compositions can be includedwith the packages as described below. The invention is further directedto medicaments of an antibody or antigen-binding fragment and apharmaceutically acceptable carrier.

Kits

Provided herein are kits that comprise one or more SH antibodies orantigen-binding fragments herein. Provided herein is a container meanscomprising one or more SH antibodies or antigen-binding fragmentsherein. The container means may be any suitable container which mayhouse a liquid or lyophilized composition including, but not limited to,a vial, a syringe, a bottle, an intravenous (IV) bag, an ampoule, or anyother suitable container. A syringe may be able to hold any volume ofliquid suitable for injection into a subject including, but not limitedto, 0.5 cc, 1 cc, 2 cc, 5 cc, 10 cc or more. In some embodiments, the SHantibody or antigen-binding fragment is lyophilized, and the kitcomprises one or more suitable buffers for reconstitution prior toinjection.

The kit may comprise one or more instruction sheets describing the useof the one or more SH antibodies or antigen-binding fragments. The kitmay include one or more labels describing the contents and use of theone or more SH antibodies.

Methods of Treatment

The present disclosure provides methods of preventing or treating asubject infected with SARS-Cov-2 (COVID) or suspected of being infectedwith SARS-Cov-2 in a subject in need thereof, comprising administeringto the subject an antibody herein. In one instance, the subject to betreated is symptomatic prior to administration of the antibody. Inanother instance, the subject to be treated is asymptomatic prior toadministration of the antibody.

The present disclosure provides methods of prophylactically treating(e.g., preventing) a subject having one or more co-morbidities or havingan increased or high risk of infection.

A “subject” as herein, includes, but is not limited to, a human, arodent, a primate, etc. In some instances, the subject to be treatedexhibits one or more underlying conditions that exacerbate the infectionsuch as, for example, high blood pressure, heart problems, diabetes,immunocompromised, lung disease, cancer, clots, thrombosis, or acombination thereof.

A subject can be administered a SH antibody or antigen-binding fragmentherein in an amount that achieves at least partially a partial orcomplete reduction of one or more symptoms. Reduction can be, forexample, a decrease of one or more symptoms by about 5% or more comparedto prior to treatment. For the administration to human patients, thecompositions can be formulated by methodology known by one in the art.The amount of an antibody necessary to bring about therapeutic treatmentof COVID19 is not fixed per se. The amount of antibody administered mayvary with the extensiveness of the disease, and size of the humansuffering from COVID19. Treatment, in one instance, lowers infectionrates in a population of subjects. Treatment may also result in ashortened recovery time, in fewer symptoms, or in less severe symptoms,or a combination thereof compared to an untreated subject who hasCOVID19.

The SH antibodies and antigen-binding fragments herein may be used totreat a COVID19 infection (an infection caused by SARS-Cov-2) in asubject in need thereof, thereby reducing one or more symptoms of theinfection. The one or more symptoms to be treated include, but are notlimited to, a fever of over 100.4° F., fatigue, coughing (e.g., a drycough), aches, pains, runny nose, stuffy nose, sore throat, diarrhea,headaches, shortness of breath, or any combination thereof. In someinstances, treatment of a subject includes a reduction by at least 5% in1 symptom, 2 symptoms, 3 symptoms, 4 symptoms, 5 symptoms, 6 symptoms, 7symptoms, 8 symptoms, 9 symptoms, 10 symptoms, or 11 symptoms. During atleast a portion of this time period the SH antibody or antigen-bindingfragment can protect the subject from infection by SARS-Cov-2.Protecting can comprise for example reducing an infection rate ofSARS-Cov-2 or reducing or preventing reproduction of SARS-Cov-2.Treatment can comprise for example reducing symptoms of COVID-19,reducing a death rate, or reducing or preventing reproduction ofSARS-Cov-2.

“Administering” is referred to herein as providing one or morecompositions to a patient in a manner that results in the compositionbeing inside the patient's body. Such an administration can be by anyroute including, without limitation, locally, regionally, orsystemically, by subcutaneous, intradermal, intravenous, intra-arterial,intraperitoneal, or intramuscular administration (e.g., injection). Inone instance, administration is via intradermal injection. In anotherinstance, administration is via subcutaneous injection. In oneembodiment, a subject is administered one of the antibodies orantigen-binding fragments herein one or more times. In anotherembodiment, a subject is administered two of the antibodies orantigen-binding fragments herein one or more times. In anotherembodiment, a subject is administered three of the antibodies orantigen-binding fragments herein one or more times. In anotherembodiment, a subject is administered four of the antibodies orantigen-binding fragments herein one or more times. A SH antibody orantigen-binding fragment herein to be administered to the subjectexhibits a nM or a pM binding affinity, e.g., between 180 pM and 50 nM.

The present disclosure provides methods of reducing the death rate ofinfection by SARS-Cov-2 by administering to a subject in need thereof acomposition comprising one or more polynucleotides (e.g., mRNA) encodingan antibody or antigen-binding fragment that can specifically bind toSARS-Cov-2. Reduction in death rate can be determined for example bycomparing the rate of death of subjects infected by SARS-Cov-2 between acohort that receives the composition and a cohort that does not receivethe composition. Death rate can be determined for example by determiningthe number of infected subjects of a cohort wherein infection bySARS-Cov-2 results in death. In some cases, the death rate can bereduced compared with subjects not administered a composition comprisingan mRNA molecule provided herein by at least 5%, at least 10%, at least20%, at least 30%, at least 40%, at least 50%, at least 60%, at least70%, at least 80%, or at least 90%. In some cases, the death rate can bereduced compared with subjects not administered a composition comprisingan mRNA molecule provided herein by about 10%, about 20%, about 30%,about 40%, about 50%, about 60%, about 70%, about 80%, about 90%, or arange between any two foregoing values.

The present disclosure also provides methods for reducing the infectionrate of SARS-Cov-2 by administering to a subject non infected withSARS-Cov-2 a composition comprising one or more polynucleotides (e.g.,mRNA) encoding an antibody or antigen-binding fragment that canspecifically bind to SARS-CoV-2. Reduction in infection rate can bedetermined for example by comparing the rate of infection of subjectsexposed to SARS-Cov-2 between a cohort that receives the composition anda cohort that does not receive the composition. Infection of a subjectcan be determined by analyzing a sample from the subject for thepresence or absence of SARS-Cov-2 after suspected or confirmed exposureto SARS-Cov-2, or after an elapsed time in which exposure to SARS-Cov-2is likely. In some cases, the infection rate can be reduced comparedwith subjects not administered a composition comprising an mRNA moleculeprovided herein by at least 5%, at least 10%, at least 20%, at least30%, at least 40%, at least 50%, at least 60%, at least 70%, at least80%, or at least 90%. In some cases, the infection rate can be reducedcompared with subjects not administered a composition comprising an mRNAmolecule provided herein by about 10%, about 20%, about 30%, about 40%,about 50%, about 60%, about 70%, about 80%, about 90%, or a rangebetween any two foregoing values.

The present disclosure also provides methods for slowing or preventingreproduction of SARS-Cov-2 in a subject by administering to a subjectinfected with SARS-Cov-2 a composition comprising one or morepolynucleotides (e.g., mRNA) encoding an antibody or antigen-bindingfragment that can specifically bind to SARS-Cov-2. Slowing or preventingreproduction of SARS-Cov-2 can be determined for example by comparingthe rate of reproduction of the virus in subjects infected SARS-Cov-2between a cohort that receives the composition and a cohort that doesnot receive the composition. Replication of SARS-Cov-2 can be determinefor example by determining (directly or indirectly) the amount ofSARS-Cov-2 in a sample acquired from the subject at different timepoints. Assays that can be used to determine amount of SARS-Cov-2 in asample can include a plaque assay, a focus forming assay, an endpointdilution assay, a protein assay (e.g., a bicinchoninic acid assay or asingle radial immunodiffusion assay), transmission electron microscopy,tunable resistive pulse sensing, flow cytometry, qPCR, ELISA, or anotheracceptable method. An assay can be performed on a whole sample or afraction of a sample, or SARS-Cov-2 can be isolated from the sampleprior to performing an assay. In some cases, the reproduction ofSARS-Cov-2 can be slowed compared with subjects not administered acomposition comprising an mRNA molecule provided herein by at least 5%,at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, atleast 60%, at least 70%, at least 80%, or at least 90%. In some cases,the reproduction of SARS-Cov-2 can be slowed compared with subjects notadministered a composition comprising an mRNA molecule provided hereinby about 10%, about 20%, about 30%, about 40%, about 50%, about 60%,about 70%, about 80%, about 90%, or a range between any two foregoingvalues.

The present disclosure also provides methods of activating T cells in asubject comprising administering to a subject a composition comprisingone or more polynucleotides (e.g., mRNA) encoding an antibody orantigen-binding fragment that can specifically bind to SARS-CoV-2. Insome cases, T cell activation can be elevated compared with subjects notadministered the composition. Activation of T cells can be determinedfor example by comparing the activation of T cells in subjects infectedSARS-Cov-2 between a cohort that receives the composition and a cohortthat does not receive the composition. In one aspect, the activation ofT cells in the subject can be directed to an anti-SARS-Cov-2 response inthe subject. Activated T cells in the subject can reduce severity ofCOVID-19 symptoms, death rate, time to recovery, or viral reproductionin the subject. Activation of T cells can be measured for example bymeasuring T cell proliferation, measuring cytokine production (e.g., viaenzyme-linked immunosorbent assays or enzyme-linked immunospot assays),or detection of cell-surface markers associated with T cell activation(e.g., CD69, CD40L, CD137, CD25, CD71, CD26, CD27, CD28, CD30, CD154, orCD134) for example by flow cytometry. In some cases, the T cellactivation can be elevated compared with subjects not administered acomposition comprising an mRNA molecule provided herein by at least 5%,at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, atleast 60%, at least 70%, at least 80%, or at least 90%. In some cases,the T cell activation can be elevated compared with subjects notadministered a composition comprising an mRNA molecule provided hereinby about 10%, about 20%, about 30%, about 40%, about 50%, about 60%,about 70%, about 80%, about 90%, or a range between any two foregoingvalues.

The present disclosure also provides methods for inducing T cellproliferation in a subject comprising administering to a subject acomposition comprising one or more polynucleotides (e.g., mRNA) encodingan antibody or antigen-binding fragment that can specifically bind toSARS-CoV-2. In some cases, T cell proliferation can be elevated comparedwith subjects not administered the composition. In some cases, T cellproliferation can be directed to an anti-SARS-Cov-2 response in thesubject. In some cases, T cell proliferation in the subject can reduceor decrease severity of COVID-19 symptoms, death rate, time to recovery,or viral reproduction in the subject. T cell proliferation can bedetermined for example by cell counting, viability staining, opticaldensity assays, or detection of cell-surface markers associated with Tcell activation (e.g., CD69, CD40L, CD137, CD25, CD71, CD26, CD27, CD28,CD30, CD154, or CD134) for example by flow cytometry. In some cases, Tcell proliferation can be elevated compared with subjects notadministered a composition comprising an mRNA molecule provided hereinby at least 5%, at least 10%, at least 20%, at least 30%, at least 40%,at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%.In some cases, T cell proliferation can be elevated compared withsubjects not administered a composition comprising an mRNA moleculeprovided herein by about 10%, about 20%, about 30%, about 40%, about50%, about 60%, about 70%, about 80%, about 90%, or a range between anytwo foregoing values.

The present disclosure also provides methods for inducing a memory Tcell response in a subject comprising administering to a subject acomposition comprising one or more polynucleotides (e.g., mRNA) encodingan antibody or antigen-binding fragment that can specifically bind toSARS-CoV-2. In some cases, a memory T cell response can be elevatedcompared with subjects not administered the composition. In some cases,a memory T cell response in the subject can reduce or decrease iseverity of COVID-19 symptoms, death rate, time to recovery, or viralreproduction in the subject. A memory T cell response can be directed toan anti-SARS-Cov-2 response in the subject. A memory T cell response canbe determined for example by measuring T cell markers associated withmemory T cells, measuring local cytokine production related to memoryimmune response, or detecting memory T cell-surface markers for exampleby flow cytometry. In some cases, the memory T cell response can beelevated compared with subjects not administered a compositioncomprising an mRNA molecule provided herein by at least 5%, at least10%, at least 20%, at least 30%, at least 40%, at least 50%, at least60%, at least 70%, at least 80%, or at least 90%. In some cases, thememory T cell response can be elevated compared with subjects notadministered a composition comprising an mRNA molecule provided hereinby about 10%, about 20%, about 30%, about 40%, about 50%, about 60%,about 70%, about 80%, about 90%, or a range between any two foregoingvalues.

A polynucleotide (e.g., mRNA) herein can be administered in any routeavailable, including, but not limited to, enteral, gastroenteral, oral,transdermal, epicutaneous, intradermal, subcutaneous, nasaladministration, intravenous, intraperitoneal, intraarterial,intramuscular, intraosseous infusion, transmucosal, insufflation, orsublingual administration. In some cases, mRNA of the present disclosurecan be administered parenterally (e.g., includes subcutaneous,intravenous, intraperitoneal, intratumoral, intramuscular,intra-articular, intra-synovial, intrasternal, intrathecal,intrahepatic, intralesional and injection or infusion techniques),intraventricularly, orally, by inhalation spray, topically, rectally,nasally, buccally, or via an implanted reservoir.

Actual dosage levels of antibody can be varied so as to obtain an amountof the active ingredient that is effective to achieve the desiredtherapeutic response without being toxic to the patient. The selecteddosage level will depend upon a variety of factors including theactivity of the particular antibody employed, the route ofadministration, the time of administration, the rate of excretion of theparticular antibody being employed, the duration of the treatment, otherdrugs, compounds and/or materials used in combination with theparticular composition employed, the age, sex, weight, condition,general health and prior medical history of the patient being treated,and like factors well known in the medical arts.

The antibodies herein can be administered to a subject in various dosingamounts and over various time frames.

A physician or veterinarian can readily determine and prescribe theeffective amount (ED50) of the antibody required. For example, thephysician or veterinarian could start doses of the antibody employed inthe composition at levels lower than that required in order to achievethe desired therapeutic effect and gradually increase the dosage untilthe desired effect is achieved. Alternatively, a dose can remainconstant.

The antibody can be administered to a patient by any convenient routesuch as described above. Regardless of the route of administrationselected, the antibodies of the present invention, which can be used ina suitable hydrated form, and/or the compositions, are formulated intoacceptable dosage forms.

Toxicity and therapeutic efficacy of compounds can be determined bystandard procedures in cell cultures or experimental animals, e.g., fordetermining the LD50 (the dose lethal to 50% of the population) and theED₅₀ (the dose therapeutically effective in 50% of the population). Thedose ratio between toxic and therapeutic effects is the therapeuticindex and it can be expressed as the ratio LD50/ED50. While compoundsthat exhibit toxic side effects may be used, care should be taken todesign a delivery system that targets such compounds to the site ofaffected tissue in order to minimize potential damage to healthy cellsand, thereby, reduce side effects.

Data obtained from cell culture assays and/or animal studies can be usedin formulating a range of dosage for use in humans. The dosage of suchcompounds lies preferably within a range of circulating concentrationsthat include the ED50 with little or no toxicity. The dosage may varywithin this range depending upon the dosage form employed and the routeof administration utilized. For any compound, a therapeuticallyeffective dose can be estimated initially from cell culture assays. Adose can be formulated in animal models to achieve a circulating plasmaconcentration arrange that includes the IC50 (i.e., the concentration ofthe test compound which achieves a half-maximal inhibition) asdetermined in cell culture. Levels in plasma can be measured, forexample, by high performance liquid chromatography. Such information canbe used to more accurately determine useful doses in humans.

It will be understood that administration of one or more of theantibodies or antigen-binding fragments herein can be supplemented byone or more additional therapies or drugs such as, for example,respiratory therapy; one or more blood thinners or anti-coagulants;statins, intubation; hydroxy chloroquine; one or more antibiotics (e.g.,doxycycline, Azithromycin, etc.); one or more decongestants (e.g.,Mucinex, Sudafed, etc.); one or more anti-histamines and/orglucocorticoids (e.g., Zyrtec, Claritin, Allegra, fluticasone luroate,etc.); one or more pain relievers (e.g., acetominophen); one or morezinc-containing medications (e.g., Zycam, etc.); Azithromycin,hydroquinolone, or a combination thereof; one or more integraseinhibitors (e.g., Bictegravir, dolutegravir (Tivicay), elvitegravir,raltegravir, or a combination thereof); one or morenucleoside/nucleotide reverse transcriptase inhibitors (NRTIs; e.g.,abacavir (Ziagen), emtricitabine (Emtriva), lamivudine (Epivir),tenofovir alafenamide fumarate (Vemlidy), tenofovir disoproxil fumarate(Viread), zidovudine (Retrovir), didanosine (Videx, Videx EC), stavudine(Zerit), or a combination thereof); a combination of NRTIs (e.g., (i)abacavir, lamivudine, and zidovudine (Trizivir), (ii) abacavir andlamivudine (Epzicom), (iii) emtricitabine and tenofovir alafenamidefumarate (Descovy), (iv) emtricitabine and tenofovir disoproxil fumarate(Truvada), (v) lamivudine and tenofovir disoproxil fumarate (Cimduo,Temixys), (vi) lamivudine and zidovudine (Combivir), etc.); acombination of Descovy and Truvada; one or more non-nucleoside reversetranscriptase inhibitors (NNRTIs; e.g., doravirine (Pifeltro), efavirenz(Sustiva), etravirine (Intelence), nevirapine (Viramune, Viramune XR),rilpivirine (Edurant), delavirdine (Rescriptor), or a combinationthereof); one or more Cytochrome P4503A (CYP3A) inhibitors (e.g.,cobicistat (Tybost), ritonavir (Norvir), etc.); one or more proteaseinhibitors (PIs; e.g., atazanavir (Reyataz), darunavir (Prezista),fosamprenavir (Lexiva), lopinavir, ritonavir (Norvir), tipranavir(Aptivus), etc.); one or PIs in combination with cobicistat, ritonavir,Lopinavir, Tipranavir, Atazanavir, fosamprenavir, indinavir (Crixivan),nelfinavir (Viracept), saquinavir (Invirase), or a combination thereof;Atazanavir; fosamprenavir; a combination of Atazanavir, darunavir andcobicistat; one or more fusion inhibitors (e.g., enfuvirtide (Fuzeon);one or more post-attachment inhibitors (e.g., ibalizumab-uiyk(Trogarzo)); one or more Chemokine coreceptor antagonists (CCR5antagonists; e.g., maraviroc (Selzentry)); and one or more viral entryinhibitors (e.g., enfuvirtide (Fuzeon), ibalizumab-uiyk (Trogarzo),maraviroc (Selzentry), etc.); or a combination thereof.

Non-limiting examples of combinations include one or more of theantibodies or antigen-binding fragments herein to be administered withone or more of the following: (1) Azithromycin, hydroquinolone, or acombination thereof, (2) darunavir and cobicistat (Prezcobix), (3)lopinavir and ritonavir (Kaletra), (4) abacavir, lamivudine, andzidovudine (Trizivir), (5) abacavir and lamivudine (Epzicom), (6)emtricitabine and tenofovir alafenamide fumarate (Descovy), (7)emtricitabine and tenofovir disoproxil fumarate (Truvada), (8)lamivudine and tenofovir disoproxil fumarate (Cimduo, Temixys), (9)lamivudine and zidovudine (Combivir), (10), atazanavir and cobicistat(Evotaz), (11) doravirine, lamivudine, and tenofovir disoproxil fumarate(Delstrigo), (12) efavirenz, lamivudine, and tenofovir disoproxilfumarate (Symfi), (13) efavirenz, lamivudine, and tenofovir disoproxilfumarate (Symfi Lo), (14) efavirenz, emtricitabine, and tenofovirdisoproxil fumarate (Atripla), (15) emtricitabine, rilpivirine, andtenofovir alafenamide fumarate (Odefsey), (16) emtricitabine,rilpivirine, and tenofovir disoproxil fumarate (Complera), (17)elvitegravir, cobicistat, emtricitabine, and tenofovir disoproxilfumarate (Stribild), (18) elvitegravir, cobicistat, emtricitabine, andtenofovir alafenamide fumarate (Genvoya), (19) abacavir, dolutegravir,and lamivudine (Triumeq), (20) bictegravir, emtricitabine, and tenofoviralafenamide fumarate (Biktarvy), (21) dolutegravir and lamivudine(Dovato), (22) dolutegravir and rilpivirine (Juluca), (23) darunavir,cobicistat, emtricitabine, and tenofovir alafenamide fumarate (Symtuza).

Non-limiting examples of combinations include one or more of theantibodies or antigen-binding fragments herein to be administered withone or more blood thinners. Blood thinners to be co-administeredinclude, but are not limited to, anti-platelet, and anti-coagulationmedications. Antiplatelet medications are those such as, for example,aspirin, clopidogrel (PLAVIX®); prasugrel (EFFIENT®); ticlopidine(TICLID®); ticagrelor (BRILINTA®); and combinations thereof.Anticoagulants include, but are not limited to, Warfarin (COUMADIN®,JANTOVEN®); Heparin (e.g., FRAGMIN®, INNOHEP®, and LOVENOX®); Eabigatran(PRADAXA®); Epixaban (ELIQUIS®); Non-vitamin K antagonist oralanticoagulants (NOACs) such as, for example, Rivaroxaban (XARELTO®);Factor Xa inhibitors such as, for example, Edoxaban (SAVAYSA®),Fondaparinux (ARIXTRA®); and combinations thereof.

Diagnostics

Provided herein are methods of diagnosing a subject suspected of beinginfected with SARS-Cov-2 by contacting a sample obtained from thesubject with one or more antibodies or antigen-binding fragments herein.

A “sample” from a subject to be tested utilizing one or more of theassays herein includes, but is not limited to, a nasal swab, a tissuesample, saliva, blood, etc. In some instances, the sample is treatedprior to use in a diagnostic assay. For example, a nasal swab may beflushed with phosphate buffered saline (PBS); a fluid sample may becentrifuged to concentrate the sample components; blood may be treatedwith heparin to prevent coagulation, etc.

Samples may be tested in any suitable assay including, but not limitedto, an enzyme linked immunosorbent assay (ELISA), an immunospot assay, alateral flow assay, immunohistochemistry (IHC), western blot, flowcytometry, etc. The sample is contacted with an antibody herein, andwhen the presence of the antibody bound to a SARS-CoV-2 is detected, thesubject is diagnosed as being infected with SARS-Cov-2 and/or having aCOVID-19 infection.

In one instance, a sample obtained from a subject is contacted with a SHantibody or antigen-binding fragment herein that selectively binds toSARS-Cov-2 and the presence or absence of the antibody orantigen-binding fragment is determined. The subject is diagnosed asbeing infected with SARS-Cov-2 when the presence of the antibody orantigen-binding fragment is detected.

Exemplary Definitions

The term “about” as used herein, generally refers to a range that is 2%,5%, 10%, 15% greater than or less than (±) a stated numerical valuewithin the context of the particular usage. For example, “about 10”would include a range from 8.5 to 11.5. As used herein, the terms“about” and “approximately,” when used to modify a numeric value ornumeric range, indicate that deviations of up to about 0.2%, about 0.5%,about 1%, about 2%, about 5%, about 7.5%, or about 10% (or any integerbetween about 1% and 10%) above or below the value or range remainwithin the intended meaning of the recited value or range.

As used in this specification and the appended claims, the singularforms “a,” “an,” and “the” include plural references unless the contextclearly dictates otherwise. Thus, for example, references to “a method”include one or more methods, and/or steps of the type herein and/orwhich will become apparent to those persons skilled in the art uponreading this disclosure.

Polypeptides (e.g., proteins) and polynucleotides (e.g., nucleic acids)herein can be isolated and/or purified from their natural environment insubstantially pure or homogeneous form. Methods of purifying proteinsand nucleic acids are contemplated for use herein. “Isolated” (usedinterchangeably with “substantially pure”) when applied to polypeptidesmeans a polypeptide or a portion thereof which, by virtue of its originor manipulation: (i) is present in a host cell as the expression productof a portion of an expression vector; (ii) is linked to a protein orother chemical moiety other than that to which it is linked in nature;or (iii) does not occur in nature, for example, a protein that ischemically manipulated by appending, or adding at least one hydrophobicmoiety to the protein so that the protein is in a form not found innature. By “isolated” it is further meant a protein that is: (i)synthesized chemically or (ii) expressed in a host cell and purifiedaway from associated and contaminating proteins. The term generallymeans a polypeptide that has been separated from other proteins andnucleic acids with which it naturally occurs. The polypeptide may alsobe separated from substances such as antibodies or gel matrices(polyacrylamide) which are used to purify it. As used herein,substantially pure, isolated,” or purified refers to material which isat least 50% pure (e.g., free from contaminants), at least 60% pure, atleast 70% pure, at least 80% pure, at least 85% pure, at least 90% pure,at least 91% pure, at least 92% pure, at least 93% pure, at least 94%pure, at least 95% pure, at least 96% pure, at least 97% pure, at least98% pure, or at least 99% pure.

Polypeptides can be isolated and purified from culture supernatant orascites by saturated ammonium sulfate precipitation, an euglobulinprecipitation method, a caproic acid method, a caprylic acid method, ionexchange chromatography (DEAE or DE52), or affinity chromatography usinganti-Ig column or a protein A, protein G, or protein L column such asdescribed in more detail below. In one aspect, reference to a bindingagent, an antibody or an antigen-binding fragment also refers to an“isolated binding agent,” an “isolated antibody,” or an “isolatedantigen-binding fragment.” In another aspect, reference to a bindingagent, an antibody, or an antigen-binding fragment also refers to a“purified binding agent,” a “purified antibody,” or a “purifiedantigen-binding fragment.”

Antibodies can be “isolated” and “purified” from the culture supernatantor ascites mentioned above by saturated ammonium sulfate precipitation,euglobulin precipitation method, caproic acid method, caprylic acidmethod, ion exchange chromatography (DEAE or DE52), or affinitychromatography using anti-Ig column or a protein A, G or L column usingart-recognized conventional methods.

As used herein, the term “antibody” refers to an immunoglobulin (Ig),polypeptide, or a protein having a binding domain which is, or ishomologous to, an antigen-binding domain. The term further includes“antigen-binding fragments” and other interchangeable terms for similarbinding fragments as described below. Native antibodies and nativeimmunoglobulins (Igs) are generally heterotetrameric glycoproteins ofabout 150,000 Daltons, composed of two identical light chains and twoidentical heavy chains. Each light chain is typically linked to a heavychain by one covalent disulfide bond, while the number of disulfidelinkages varies among the heavy chains of different immunoglobulinisotypes. Each heavy and light chain also has regularly spacedintrachain disulfide bridges. Each heavy chain has at one end a variabledomain (“VH”) followed by a number of constant domains (“C_(H)”). Eachlight chain has a variable domain at one end (“VL”) and a constantdomain (“CL”) at its other end; the constant domain of the light chainis aligned with the first constant domain of the heavy chain, and thelight-chain variable domain is aligned with the variable domain of theheavy chain. Particular amino acid residues are believed to form aninterface between the light- and heavy-chain variable domains. In someinstances, an antibody or an antigen-binding fragment comprises anisolated antibody or antigen-binding fragment, a purified antibody orantigen-binding fragment, a recombinant antibody or antigen-bindingfragment, a modified antibody or antigen-binding fragment, or asynthetic antibody or antigen-binding fragment.

Antibodies and antigen-binding fragments herein can be partly or whollysynthetically produced. An antibody or antigen-binding fragment can be apolypeptide or protein having a binding domain which can be, or can behomologous to, an antigen-binding domain. In one instance, an antibodyor an antigen-binding fragment can be produced in an appropriate in vivoanimal model and then isolated and/or purified. It would be understoodthat the antibodies herein can be modified as described below or asknown in the art.

Antibodies useful in the present invention encompass, but are notlimited to, monoclonal antibodies, polyclonal antibodies, antibodyfragments (e.g., Fab, Fab′, F(ab′)₂, Fv, Fc, scFv, scFv-Fc, Fab-Fc,scFv-zipper, scFab, crossFab, camelids (VHH), etc.), chimericantibodies, bispecific antibodies, multispecific antibodies,heteroconjugate antibodies, single chain (ScFv), mutants thereof, fusionproteins comprising an antibody portion (e.g., a domain antibody),humanized antibodies, human antibodies, and any other modifiedconfiguration of the immunoglobulin molecule that comprises an antigenrecognition site of the required specificity, including glycosylationvariants of antibodies, amino acid sequence variants of antibodies, andcovalently modified antibodies.

Depending on the amino acid sequence of the constant domain of its heavychains, immunoglobulins (Igs) can be assigned to different classes.There are five major classes of immunoglobulins: IgA, IgD, IgE, IgG, andIgM, and several of these may be further divided into subclasses(isotypes), e.g., IgG1, IgG2, IgG3, IgG4, IgA1 and IgA2. An Ig orportion thereof can, in some cases, be a human Ig. In some instances, aC_(H)3 domain can be from an immunoglobulin. In some cases, a chain or apart of an antibody or antigen-binding fragment, a modified antibody orantigen-binding fragment, or a binding agent can be from an Ig. In suchcases, an Ig can be IgG, an IgA, an IgD, an IgE, or an IgM. In caseswhere the Ig is an IgG, it can be a subtype of IgG, wherein subtypes ofIgG can include IgG1, an IgG2a, an IgG2b, an IgG3, and an IgG4. In somecases, a C_(H)3 domain can be from an immunoglobulin selected from thegroup consisting of an IgG, an IgA, an IgD, an IgE, and an IgM.

The “light chains” of antibodies (immunoglobulins) from any vertebratespecies can be assigned to one of two clearly distinct types, calledkappa or (“κ” or “K”) and lambda or (“λ”), based on the amino acidsequences of their constant domains.

As used herein, a “monoclonal antibody” refers to an antibody obtainedfrom a population of substantially homogeneous antibodies, e.g., theindividual antibodies comprising the population are identical except forpossible naturally-occurring mutations that may be present in minoramounts. In contrast to polyclonal antibody preparations, whichtypically include different antibodies directed against differentdeterminants (epitopes), each monoclonal antibody is directed against asingle determinant on the antigen (epitope). The modifier “monoclonal”indicates the character of the antibody as being obtained from asubstantially homogeneous population of antibodies, and is not to beconstrued as requiring production of the antibody by any particularmethod. For example, the monoclonal antibodies to be used in accordancewith the present invention may be made by the hybridoma method firstdescribed by Kohler and Milstein, 1975, Nature, 256:495, or may be madeby recombinant DNA methods such as described in U.S. Pat. No. 4,816,567.The monoclonal antibodies may also be isolated from phage librariesgenerated using the techniques described in McCafferty et al., 1990,Nature, 348:552-554, for example. Other methods are known in the art andare contemplated for use herein.

A “variable region” of an antibody refers to the variable region of theantibody light chain or the variable region of the antibody heavy chain,either alone or in combination. The variable regions of the heavy andlight chain each consist of four framework regions (FR) connected bythree complementarity determining regions (CDRs) also known ashypervariable regions. The CDRs in each chain are held together in closeproximity by the FRs and, with the CDRs from the other chain, contributeto the formation of the antigen-binding site of antibodies. Amino acidresidues of CDRs and framework regions are as herein for the providedsequences.

With respect to antibodies, the term “variable domain” refers to thevariable domains of antibodies that are used in the binding andspecificity of each particular antibody for its particular antigen.However, the variability is not evenly distributed throughout thevariable domains of antibodies. Rather, it is concentrated in threesegments called hypervariable regions (also known as CDRs) in both thelight chain and the heavy chain variable domains. More highly conservedportions of variable domains are called the “framework regions,” “FWs,”or “FRs.” The variable domains of unmodified heavy and light chains eachcontain four FRs (FR1, FR2, FR3, and FR4), largely adopting a β-sheetconfiguration interspersed with three CDRs which form loops connectingand, in some cases, part of the β-sheet structure. The CDRs in eachchain are held together in close proximity by the FRs and, with the CDRsfrom the other chain, contribute to the formation of the antigen-bindingsite of antibodies.

A “constant region” of an antibody refers to the constant region of theantibody light chain or the constant region of the antibody heavy chain,either alone or in combination.

“Epitope” refers to that portion of an antigen or other macromoleculecapable of forming a binding interaction with the variable regionbinding pocket of an antibody. Such binding interactions can bemanifested as an intermolecular contact with one or more amino acidresidues of one or more CDRs. Antigen-binding can involve, for example,a CDR3 or a CDR3 pair or, in some cases, interactions of up to all sixCDRs of the VH and VL chains. An epitope can be a linear peptidesequence (“continuous”) or can be composed of noncontiguous amino acidsequences (“conformational” or “discontinuous”). An antibody canrecognize one or more amino acid sequences; therefore, an epitope candefine more than one distinct amino acid sequence. Epitopes recognizedby antibodies can be determined by peptide mapping and sequence analysistechniques well known to one of skill in the art. Binding interactionsare manifested as intermolecular contacts between an epitope on anantigen and one or more amino acid residues of a CDR. An epitopeprovided herein can refer to an amino acid sequence on a receptorbinding domain or a spike domain.

An antibody selectively binds to a target if it binds with greateraffinity, avidity, more readily, and/or with greater duration than itbinds to other substances. For example, an antibody or antigen-bindingfragment that selectively binds to a SARS-Cov-2 epitope is an antibodyor antigen-binding fragment that binds this epitope with greateraffinity, avidity, more readily, and/or with greater duration than itbinds to SARS-Cov-1 or MERS. The term “Fc region” is used to define aC-terminal region of an immunoglobulin heavy chain. The “Fc region” maybe a native sequence Fc region or a variant Fc region. Although theboundaries of the Fc region of an immunoglobulin heavy chain might vary,the human IgG heavy chain Fc region is usually defined to stretch froman amino acid residue at position Cys226, or from Pro230, to thecarboxyl-terminus thereof. The Fc region of an immunoglobulin generallycomprises two constant domains, CH2 and CH3.

The terms “hypervariable region” and “CDR” when used herein, refer tothe amino acid residues of an antibody which are responsible forantigen-binding. The CDRs comprise amino acid residues from threesequence regions which bind in a complementary manner to an antigen andare known as CDR1, CDR2, and CDR3 for each of the VH and VL chains. Itis understood that the CDRs of different antibodies may containinsertions, thus the amino acid numbering may differ. CDR sequences ofthe antibodies and antigen-binding fragments thereof have been providedherein below.

As used herein, “framework region” or “FR” or “FW” refers to frameworkamino acid residues that form a part of the antigen-binding pocket orgroove. In some embodiments, the framework residues form a loop that isa part of the antigen-binding pocket or groove and the amino acidsresidues in the loop may or may not contact the antigen. Frameworkregions generally comprise the regions between the CDRs. Frameworkregions of the antibodies and antigen-binding fragments thereof havebeen provided herein below.

The loop amino acids of a FR can be assessed and determined byinspection of the three-dimensional structure of an antibody heavy chainand/or antibody light chain. The three-dimensional structure can beanalyzed for solvent accessible amino acid positions as such positionsare likely to form a loop and/or provide antigen contact in an antibodyvariable domain. Some of the solvent accessible positions can tolerateamino acid sequence diversity and others (e.g., structural positions)are, generally, less diversified. The three-dimensional structure of theantibody variable domain can be derived from a crystal structure orprotein modeling.

In the present disclosure, the following abbreviations (in theparentheses) are used in accordance with the customs, as necessary:heavy chain (H chain), light chain (L chain), heavy chain variableregion (VH), light chain variable region (VL), complementaritydetermining region (CDR), first complementarity determining region(CDR1), second complementarity determining region (CDR2), thirdcomplementarity determining region (CDR3), heavy chain firstcomplementarity determining region (VH CDR1), heavy chain secondcomplementarity determining region (VH CDR2), heavy chain thirdcomplementarity determining region (VH CDR3), light chain firstcomplementarity determining region (VL CDR1), light chain secondcomplementarity determining region (VL CDR2), and light chain thirdcomplementarity determining region (VL CDR3).

In some instances, an anti-SARS-Cov-2 antibody is a monoclonal antibody.As used herein, a “monoclonal antibody” refers to an antibody obtainedfrom a population of substantially homogeneous antibodies, i.e., theindividual antibodies comprising the population are identical except forpossible naturally-occurring mutations that may be present in minoramounts. In contrast to polyclonal antibody preparations, whichtypically include different antibodies directed against differentdeterminants (epitopes), each monoclonal antibody is directed against asingle determinant on the antigen (epitope). The modifier “monoclonal”indicates the character of the antibody as being obtained from asubstantially homogeneous population of antibodies and is not to beconstrued as requiring production of the antibody by any particularmethod, including the Tumbler methods described below.

In some instances, an anti-SARS-Cov-2 antibody or antigen-bindingfragment is a humanized antibody or a humanized antigen-bindingfragment. As used herein, “humanized” antibodies refer to forms ofnon-human (e.g., murine) antibodies that are specific chimericimmunoglobulins, immunoglobulin chains, or fragments thereof thatcontain minimal sequence derived from non-human immunoglobulin. For themost part, humanized antibodies are human immunoglobulins (recipientantibody) in which residues from a complementarity determining region(CDR) of the recipient are replaced by residues from a CDR of anon-human species (donor antibody) such as mouse, rat, or rabbit havingthe desired specificity, affinity, and biological activity. In someinstances, Fv framework region (FR) residues of the human immunoglobulinare replaced by corresponding non-human residues. Furthermore, thehumanized antibody may comprise residues that are found neither in therecipient antibody nor in the imported CDR or framework sequences, butare included to further refine and optimize antibody performance. Ingeneral, a humanized antibody comprises substantially all of at leastone, and typically two, variable domains, in which all or substantiallyall of the CDR regions correspond to those of a non-human immunoglobulinand all or substantially all of the FR regions are those of a humanimmunoglobulin consensus sequence. The humanized antibody optimally alsowill comprise at least a portion of an immunoglobulin constant region ordomain (Fc), typically that of a human immunoglobulin. Antibodies mayhave Fc regions modified as described in, for example, WO 99/58572.Other forms of humanized antibodies have one or more CDRs (one, two,three, four, five, or six) which are altered with respect to theoriginal antibody, which are also termed one or more CDRs “derived from”one or more CDRs from the original antibody.

If needed, an antibody or an antigen-binding fragment herein can beassessed for immunogenicity and, as needed, be deimmunized (i.e., theantibody is made less immunoreactive by altering one or more T cellepitopes). As used herein, a “deimmunized antibody” means that one ormore T cell epitopes in an antibody sequence have been modified suchthat a T cell response after administration of the antibody to a subjectis reduced compared to an antibody that has not been deimmunized.Analysis of immunogenicity and T-cell epitopes present in the antibodiesand antigen-binding fragments herein can be carried out via the use ofsoftware and specific databases. Exemplary software and databasesinclude iTope™ developed by Antitope of Cambridge, England. iTope™, isan in silico technology for analysis of peptide binding to human MEWclass II alleles. The iTope™ software predicts peptide binding to humanMEW class II alleles and thereby provides an initial screen for thelocation of such “potential T cell epitopes.” iTope™ software predictsfavorable interactions between amino acid side chains of a peptide andspecific binding pockets within the binding grooves of 34 human MHCclass II alleles. The location of key binding residues is achieved bythe in silico generation of 9mer peptides that overlap by one amino acidspanning the test antibody variable region sequence. Each 9mer peptidecan be tested against each of the 34 MHC class II allotypes and scoredbased on their potential “fit” and interactions with the MHC class IIbinding groove. Peptides that produce a high mean binding score (>0.55in the iTope™ scoring function) against >50% of the MHC class II allelesare considered as potential T cell epitopes. In such regions, the core 9amino acid sequence for peptide binding within the MHC class II grooveis analyzed to determine the MHC class II pocket residues (P1, P4, P6,P7, and P9) and the possible T cell receptor (TCR) contact residues(P-1, P2, P3, P5, P8). After identification of any T-cell epitopes,amino acid residue changes, substitutions, additions, and/or deletionscan be introduced to remove the identified T-cell epitope. Such changescan be made so as to preserve antibody structure and function whilestill removing the identified epitope. Exemplary changes can include,but are not limited to, conservative amino acid changes.

An anti-SARS-Cov-2 antibody or antigen-binding fragment can be a humanantibody or human antigen-binding fragment. As used herein, a “humanantibody” means an antibody having an amino acid sequence correspondingto that of an antibody produced by a human and/or that has been madeusing any suitable technique for making human antibodies. Thisdefinition of a human antibody includes antibodies comprising at leastone human heavy chain polypeptide or at least one human light chainpolypeptide. One such example is an antibody comprising murine lightchain and human heavy chain polypeptides. In one embodiment, the humanantibody is selected from a phage library, where that phage libraryexpresses human antibodies (Vaughan et al., 1996, Nature Biotechnology,14:309-314; Sheets et al., 1998, PNAS USA, 95:6157-6162; Hoogenboom andWinter, 1991, J. Mol. Biol., 227:381; Marks et al., 1991, J. Mol. Biol.,222:581). Human antibodies can also be made by introducing humanimmunoglobulin loci into transgenic animals, e.g., mice in which theendogenous immunoglobulin genes have been partially or completelyinactivated. This approach is described in U.S. Pat. Nos. 5,545,807;5,545,806; 5,569,825; 5,625,126; 5,633,425; and 5,661,016.Alternatively, the human antibody may be prepared by immortalizing humanB lymphocytes that produce an antibody directed against a target antigen(such B lymphocytes may be recovered from an individual or may have beenimmunized in vitro). See, e.g., Cole et al., Monoclonal Antibodies andCancer Therapy, Alan R. Liss, p. 77 (1985); Boerner et al., 1991, J.Immunol., 147 (1):86-95; and U.S. Pat. No. 5,750,373.

Any of the anti-SARS-Cov-2 antibodies, or antigen-binding fragmentsherein can be bispecific. Bispecific antibodies are antibodies that havebinding specificities for at least two different antigens or differentaffinities for the same antigen. Bispecific antibodies can be preparedusing the antibodies or antigen-binding fragments disclosed herein.Methods for making bispecific antibodies are described (see, e.g.,Suresh et al., 1986, Methods in Enzymology 121:210). Traditionally, therecombinant production of bispecific antibodies was based on theco-expression of two immunoglobulin heavy chain-light chain pairs, withthe two heavy chains having different specificities (Millstein andCuello, 1983, Nature, 305, 537-539). Bispecific antibodies can becomposed of a hybrid immunoglobulin heavy chain with a first bindingspecificity in one arm, and a hybrid immunoglobulin heavy chain-lightchain pair (providing a second binding specificity) in the other arm.This asymmetric structure, with an immunoglobulin light chain in onlyone half of the bispecific molecule, facilitates the separation of thedesired bispecific compound from unwanted immunoglobulin chaincombinations. Bispecific antibody fragments may be connected via alinker. This approach is described in PCT Publication No. WO 94/04690.

According to one approach to making bispecific antibodies, antibodyvariable domains with the desired binding specificities(antibody-antigen combining sites) are fused to immunoglobulin constantdomain sequences. The fusion can be with an immunoglobulin heavy chainconstant domain, comprising at least part of the hinge, CH2 and CH3regions. The first heavy chain constant region (CH1), containing thesite necessary for light chain binding, can be present in at least oneof the fusions. DNAs encoding the immunoglobulin heavy chain fusionsand, if desired, the immunoglobulin light chain, are inserted intoseparate expression vectors, and are co-transfected into a suitable hostorganism. This provides for great flexibility in adjusting the mutualproportions of the three polypeptide fragments in embodiments whenunequal ratios of the three polypeptide chains used in the constructionprovide the optimum yields. It is, however, possible to insert thecoding sequences for two or all three polypeptide chains in oneexpression vector when the expression of at least two polypeptide chainsin equal ratios results in high yields or when the ratios are of noparticular significance.

Heteroconjugate antibodies, comprising two covalently joined antibodies,are also within the scope of the disclosure. Such antibodies have beenused to target immune system cells to unwanted cells (U.S. Pat. No.4,676,980). Heteroconjugate antibodies may be made using any suitablecross-linking methods. Suitable cross-linking agents and techniques aredescribed, for example, in U.S. Pat. No. 4,676,980.

In some instances, an anti-SARS-Cov-2 antibody herein is a chimericantibody. “Chimeric” forms of non-human (e.g., murine) antibodiesinclude chimeric antibodies which contain minimal sequence derived froma non-human Ig. For the most part, chimeric antibodies are murineantibodies in which at least a portion of an immunoglobulin constantregion (Fc), typically that of a human immunoglobulin, is inserted inplace of the murine Fc. Chimeric or hybrid antibodies also may beprepared in vitro using suitable methods of synthetic protein chemistry,including those involving cross-linking agents. For example,immunotoxins may be constructed using a disulfide exchange reaction orby forming a thioether bond. Examples of suitable reagents for thispurpose include iminothiolate and methyl-4-mercaptobutyrimidate.

Provided herein are antibodies and antigen-binding fragments thereof,modified antibodies and antigen-binding fragments thereof, and bindingagents that specifically bind to one or more epitopes on one or moretarget antigens. In one instance, a binding agent selectively binds toan epitope on a single antigen. In another instance, a binding agent isbivalent and either selectively binds to two distinct epitopes on asingle antigen or binds to two distinct epitopes on two distinctantigens. In another instance, a binding agent is multivalent (i.e.,trivalent, quatravalent, etc.) and the binding agent binds to three ormore distinct epitopes on a single antigen or binds to three or moredistinct epitopes on two or more (multiple) antigens.

Functional fragments of any of the antibodies herein are alsocontemplated. The terms “antigen-binding portion of an antibody,”“antigen-binding fragment,” “antigen-binding domain,” “antibodyfragment,” or a “functional fragment of an antibody” are usedinterchangeably herein to refer to one or more fragments of an antibodythat retain the ability to specifically bind to an antigen.Representative antigen-binding fragments include, but are not limitedto, a Fab, a Fab′, a F(ab′)₂, a Fv, a scFv, a dsFv, a variable heavydomain, a variable light domain, a variable NAR domain, bi-specificscFv, a bi-specific Fab₂, a tri-specific Fab₃, an AVIMER®, a minibody, adiabody, a maxibody, a camelid, a VHH, an intrabody, fusion proteinscomprising an antibody portion (e.g., a domain antibody), a single chainbinding polypeptide, a scFv-Fc, or a Fab-Fc.

“F(ab′)₂” and “Fab′” moieties can be produced by treating an Ig with aprotease such as pepsin and papain, and include antibody fragmentsgenerated by digesting immunoglobulin near the disulfide bonds existingbetween the hinge regions in each of the two heavy chains. For example,papain cleaves IgG upstream of the disulfide bonds existing between thehinge regions in each of the two heavy chains to generate two homologousantibody fragments in which an light chain composed of V_(L) and C_(L)(light chain constant region), and a heavy chain fragment composed ofV_(H) and C_(Hγ1) (γ1) region in the constant region of the heavy chain)are connected at their C terminal regions through a disulfide bond. Eachof these two homologous antibody fragments is called Fab′. Pepsin alsocleaves IgG downstream of the disulfide bonds existing between the hingeregions in each of the two heavy chains to generate an antibody fragmentslightly larger than the fragment in which the two above-mentioned Fab′are connected at the hinge region. This antibody fragment is calledF(ab′)₂.

The Fab fragment also contains the constant domain of the light chainand the first constant domain (C_(H)1) of the heavy chain. Fab′fragments differ from Fab fragments by the addition of a few residues atthe carboxyl terminus of the heavy chain C_(H)1 domain including one ormore cysteine(s) from the antibody hinge region. Fab′-SH is thedesignation herein for Fab′ in which the cysteine residue(s) of theconstant domains bear a free thiol group. F(ab′)₂ antibody fragmentsoriginally were produced as pairs of Fab′ fragments which have hingecysteines between them. Other chemical couplings of antibody fragmentsare also known.

A “Fv” as used herein refers to an antibody fragment which contains acomplete antigen-recognition and antigen-binding site. This regionconsists of a dimer of one heavy chain and one light chain variabledomain in tight, non-covalent or covalent association (disulfide linkedFvs have been described, see, e.g., Reiter et al. (1996) NatureBiotechnology 14:1239-1245). It is in this configuration that the threeCDRs of each variable domain interact to define an antigen-binding siteon the surface of the V_(H)-V_(L) dimer. Collectively, a combination ofone or more of the CDRs from each of the V_(H) and V_(L) chains conferantigen-binding specificity to the antibody. For example, it would beunderstood that, for example, the CDRH3 and CDRL3 could be sufficient toconfer antigen-binding specificity to an antibody when transferred toV_(H) and V_(L) chains of a recipient antibody or antigen-bindingfragment and this combination of CDRs can be tested for binding,specificity, affinity, etc. using any of the techniques herein. Even asingle variable domain (or half of an Fv comprising only three CDRsspecific for an antigen) has the ability to recognize and bind antigen,although likely at a lower specificity or affinity than when combinedwith a second variable domain. Furthermore, although the two domains ofa Fv fragment (V_(L) and V_(H)) are coded for by separate genes, theycan be joined using recombinant methods by a synthetic linker thatenables them to be made as a single protein chain in which the V_(L) andV_(H) regions pair to form monovalent molecules (known as single chainFv (scFv); Bird et al. (1988) Science 242:423-426; Huston et al. (1988)Proc. Natl. Acad. Sci. USA 85:5879-5883; and Osbourn et al. (1998) Nat.Biotechnol. 16:778). Such scFvs are also intended to be encompassedwithin the term “antigen-binding portion” of an antibody. Any V_(H) andV_(L) sequences of specific scFv can be linked to an Fc region cDNA orgenomic sequences in order to generate expression vectors encodingcomplete Ig (e.g., IgG) molecules or other isotypes. V_(H) and V_(L) canalso be used in the generation of Fab, Fv, or other fragments of Igsusing either protein chemistry or recombinant DNA technology.

“Single-chain Fv” or “sFv” antibody fragments comprise the V_(H) andV_(L) domains of an antibody, wherein these domains are present in asingle polypeptide chain. In some embodiments, the Fv polypeptidefurther comprises a polypeptide linker between the V_(H) and V_(L)domains which enables the sFv to form the desired structure forantigen-binding. For a review of sFvs, see, e.g., Pluckthun in ThePharmacology of Monoclonal Antibodies, Vol. 113, Rosenburg and Mooreeds. Springer-Verlag, New York, pp. 269-315 (1994).

The term “AVIMER®” refers to a class of therapeutic proteins of humanorigin, which are unrelated to antibodies and antibody fragments, andare composed of several modular and reusable binding domains, referredto as A-domains (also referred to as class A module, complement typerepeat, or LDL-receptor class A domain). They were developed from humanextracellular receptor domains by in vitro exon shuffling and phagedisplay (Silverman et al., 2005, Nat. Biotechnol. 23:1493-1494;Silverman et al., 2006, Nat. Biotechnol. 24:220). The resulting proteinscan contain multiple independent binding domains that can exhibitimproved affinity and/or specificity compared with single-epitopebinding proteins. Each of the known 217 human A-domains comprises ˜35amino acids (˜4 kDa); and these domains are separated by linkers thataverage five amino acids in length. Native A-domains fold quickly andefficiently to a uniform, stable structure mediated primarily by calciumbinding and disulfide formation. A conserved scaffold motif of only 12amino acids is required for this common structure. The end result is asingle protein chain containing multiple domains, each of whichrepresents a separate function. Each domain of the proteins bindsindependently, and the energetic contributions of each domain areadditive.

Antigen-binding polypeptides also include heavy chain dimers such as,for example, antibodies from camelids and sharks. Camelid and sharkantibodies comprise a homodimeric pair of two chains of V-like andC-like domains (neither has a light chain). Since the V_(H) region of aheavy chain dimer IgG in a camelid does not have to make hydrophobicinteractions with a light chain, the region in the heavy chain thatnormally contacts a light chain is changed to hydrophilic amino acidresidues in a camelid. V_(H) domains of heavy-chain dimer IgGs arecalled V_(HH) domains. Shark Ig-NARs comprise a homodimer of onevariable domain (termed a V-NAR domain) and five C-like constant domains(C-NAR domains). In camelids, the diversity of antibody repertoire isdetermined by the CDRs 1, 2, and 3 in the V_(H) or V_(HH) regions. TheCDR3 in the camel V_(HH) region is characterized by its relatively longlength, averaging 16 amino acids (Muyldermans et al., 1994, ProteinEngineering 7(9): 1129). This is in contrast to CDR3 regions ofantibodies of many other species. For example, the CDR3 of mouse V_(H)has an average of 9 amino acids. Libraries of camelid-derived antibodyvariable regions, which maintain the in vivo diversity of the variableregions of a camelid, can be made by, for example, the methods disclosedin U.S. Patent Application Ser. No. 20050037421.

As used herein, a “maxibody” refers to a bivalent scFv covalentlyattached to the Fc region of an immunoglobulin, see, e.g., Fredericks etal., Protein Engineering, Design & Selection, 17:95-106 (2004) andPowers et al., Journal of Immunological Methods, 251:123-135 (2001).

As used herein, a “dsFv” can be a Fv fragment obtained by introducing aCys residue into a suitable site in each of a heavy chain variableregion and a light chain variable region, and then stabilizing the heavychain variable region and the light chain variable region by a disulfidebond. The site in each chain, into which the Cys residue is to beintroduced, can be determined based on a conformation predicted bymolecular modeling. In the present disclosure, for example, aconformation is predicted from the amino acid sequences of the heavychain variable region and light chain variable region of theabove-described antibody, and DNA encoding each of the heavy chainvariable region and the light chain variable region, into which amutation has been introduced based on such prediction, is thenconstructed. The DNA construct is incorporated then into a suitablevector and prepared from a transformant obtained by transformation withthe aforementioned vector.

Single chain variable region fragments (“scFv”) of antibodies areherein. Single chain variable region fragments may be made by linkinglight and/or heavy chain variable regions by using a short linkingpeptide. Bird et al. (1988) Science 242:423-426. The single chainvariants can be produced either recombinantly or synthetically. Forsynthetic production of scFv, an automated synthesizer can be used. Forrecombinant production of scFv, a suitable plasmid containingpolynucleotide that encodes the scFv can be introduced into a suitablehost cell, either eukaryotic, such as yeast, plant, insect, or mammaliancells, or prokaryotic, such as E. coli. Polynucleotides encoding thescFv of interest can be made by routine manipulations such as ligationof polynucleotides. The resultant scFv can be isolated using anysuitable protein purification techniques.

Diabodies can be single chain antibodies. Diabodies can be bivalent,bispecific antibodies in which VH and VL domains are expressed on asingle polypeptide chain, but using a linker that is too short to allowfor pairing between the two domains on the same chain, thereby forcingthe domains to pair with complementary domains of another chain andcreating two antigen-binding sites (see, e.g., Holliger, P., et al.,Proc. Natl. Acad. Sci. USA, 90:6444-6448 (1993); and Poljak, R. J., etal., Structure, 2:1121-1123 (1994)).

As used herein, a “minibody” refers to a scFv fused to CH3 via a peptidelinker (hingeless) or via an IgG hinge has been described in Olafsen, etal., Protein Eng. Des. Sel., April 2004; 17(4):315-23.

As used herein, an “intrabody” refers to a single chain antibody whichdemonstrates intracellular expression and can manipulate intracellularprotein function (Biocca, et al., EMBO J. 9:101-108, 1990; Colby et al.,Proc Natl Acad. Sci. USA. 101:17616-21, 2004). Intrabodies, whichcomprise cell signal sequences which retain the antibody construct inintracellular regions, may be produced as described in Mhashilkar etal., (EMBO J., 14:1542-51, 1995) and Wheeler et al. (FASEB J. 17:1733-5.2003). Transbodies are cell-permeable antibodies in which a proteintransduction domains (PTD) is fused with single chain variable fragment(scFv) antibodies Heng et al. (Med Hypotheses. 64:1105-8, 2005).

A “scFv-Fc” fragment as herein refers to an scFv attached to an Fcdomain. For example, an Fc domain may be attached to the C-terminal ofthe scFv. The Fc domain may follow the VH or VL, depending on theorientation of the variable domains in the scFv (i.e., VH-VL or VL). Anysuitable Fc domain known in the art or herein may be used. In somecases, the Fc domain comprises an IgG1 Fc domain or an IgG4 Fc domain. AscFv-Fc format allows for rapid characterization of candidate scFvsisolated from phage display libraries before conversion into afull-length IgG. This format offers several advantages over the phagedisplay-derived scFv, including bivalent binding, longer half-life, andFc-mediated effector functions. Here, a detailed method is presented,which describes the cloning, expression, and purification of an scFv-Fcfragment, starting from scFv fragments obtained from a phage displaylibrary. This method facilitates the rapid screening of candidateantibodies, prior to a more time-consuming conversion into a full IgGformat. In one instance, a single-chain Fv (scFv) includes the heavy andlight chains in the Fv of an anti-SARS-Cov-2 antibody herein joined witha flexible peptide linker (e.g., of about 10, 12, 15 or more amino acidresidues) in a single peptide chain. The single chain antibody may bemonovalent, if only a single VH and VL are used, bivalent, if two VH andVL are used, or polyvalent, if more than two VH and VL are used. In someinstances, the entire Fc region is attached to the scFv. In otherinstances, only the CH3 region of a Fc is attached to the scFv (a“scFv-CH).

A “scFab” as herein refers to an antigen-binding domain thatspecifically binds to SARS-Cov-2 is fused via a peptide linker to theC-terminus to one of the heavy chains.

A “scFv zipper” as herein refers to constructs of leucine zipper-baseddimerization cassettes for the conversion of recombinant monomeric scFvantibody fragments to bivalent and bispecific dimers. A truncated murineIgG3 hinge region and a Fos or Jun leucine zipper are cloned into fourscFv fragments. Cysteine residues flanking the zipper region areintroduced to covalently link dimerized scFv fragments. The secretedfusion proteins form stable Fos⋅Fos or Jun⋅Jun homodimers.

A “cross-Fab fragment” or “xFab fragment” or “crossover Fab fragment” asherein refers to a Fab fragment, wherein either the variable regions orthe constant regions of the heavy and light chain are exchanged. Twodifferent chain compositions of a crossover Fab molecule are possibleand comprised within the scope of bispecific antibodies andantigen-binding fragments herein. On the one hand, the variable regionsof the Fab heavy and light chain are exchanged, i.e. the crossover Fabmolecule comprises a peptide chain composed of the light chain variableregion (VL) and the heavy chain constant region (CH1), and a peptidechain composed of the heavy chain variable region (VH) and the lightchain constant region (CL). This crossover Fab molecule is also referredto as CrossFab VLVH. On the other hand, when the constant regions of theFab heavy and light chain are exchanged, the crossover Fab moleculecomprises a peptide chain composed of the heavy chain variable region(VH) and the light chain constant region (CL), and a peptide chaincomposed of the light chain variable region (VL) and the heavy chainconstant region (CH1). This crossover Fab molecule is also referred toas CrossFab CLCH1.

A “Fab-Fc” fragment as herein refers to a Fab fragment that is attachedto a CH1, CH2, and/or a CH3 region of a Fc, where the molecule does notcontain all of a CH1, CH2, and CH3.

The terms “single domain antibody” and “sdAb” refer to a single-chainantibody polypeptide consisting of a single monomeric variable antibodydomain. The term “VHH” as used herein refers to molecules engineeredfrom heavy-chain antibodies found in camelids. The terms “shark newantigen receptor”, “VNAR” and “IgNAR” as used herein refer to moleculesobtained from the heavy-chain antibodies of cartilaginous fish, such assharks. Single-domain antibodies can also be obtained by splittingdimeric variable domains from common immunoglobulin G (IgG) intomonomers. Single-domain antibodies are typically about 110 amino acidslong and have a typical molecular weight in the region of from about 12to about 15 kDa. As such, single-domain antibodies are much smaller thancommon antibodies (150-160 kDa), and even smaller than Fab fragments(which consist of one light chain and half a heavy chain and have amolecular weight of about 50 kDa) and single-chain variable fragments(which consist of two variable domains, one from a light and one from aheavy chain, and have a molecular weight of about 25 kDa).

Suitable linkers may be used to link various parts of recombinant orsynthetic antibodies or antigen-binding fragments thereof or tomultimerize binding agents. A non-limiting example of a linking peptideis (GGGGS)_(n), where n=3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,17, 18, 19, 20, or more (SEQ ID NO: 443) and which bridges approximately3.5 nm between the carboxy terminus of one variable region and the aminoterminus of the other variable region. Linkers of other sequences havebeen designed and used. Methods of producing such antibodies aredescribed in for instance U.S. Pat. No. 4,946,778, Pluckthun in ThePharmacology of Monoclonal Antibodies, vol. 113, Rosenburg and Mooreeds. Springer-Verlag, New York, pp. 269-315 (1994), Bird et al., Science242, 423-426 (1988), Huston et al., PNAS USA 85, 5879-5883 (1988) andMcCafferty et al., Nature 348, 552-554 (1990). Linkers can in turn bemodified for additional functions, such as attachment of drugs orattachment to solid supports. Fab and scFab fragments may be stabilizedvia natural disulfide bonds between the CL domain and the CH1 domain.Antigen-binding fragments comprising a heavy chain variable domain (VH)and a light chain variable domain (VL), such as the Fab, crossFab, scFvand scFab fragments as herein might be further stabilized by introducinginterchain disulfide bridges between the VH and the VL domain.Accordingly, in one embodiment, the Fab fragment(s), the crossFabfragment(s), the scFv fragment(s) and/or the scFab fragment(s) comprisedin the antigen-binding receptors according to the invention might befurther stabilized by generation of interchain disulfide bonds viainsertion of cysteine residues. Such stabilized antigen-binding moietiesare referred to by the term “ds”. Cysteine engineered antibodies, insome embodiments, are made reactive for conjugation with linker-degraderintermediates herein, by treatment with a reducing agent such as DTT(Cleland's reagent, dithiothreitol) or TCEP(tris(2-carboxyethyl)phosphine hydrochloride; Getz et al. (1999) Anal.Biochem. Vol 273:73-80; Soltec Ventures, Beverly, Mass.) followed byre-formation of the inter-chain disulfide bonds (re-oxidation) with amild oxidant such as dehydroascorbic acid.

Also provided herein are affinity matured antibodies. For example,affinity matured antibodies can be produced by any suitable procedure(see, e.g., Marks et al., 1992, Bio/Technology, 10:779-783; Barbas etal., 1994, Proc Nat. Acad. Sci, USA 91:3809-3813; Schier et al., 1995,Gene, 169:147-155; Yelton et al., 1995, J. Immunol., 155:1994-2004;Jackson et al., 1995, J. Immunol., 154(7):3310-9; Hawkins et al, 1992,J. Mol. Biol., 226:889-896; and WO2004/058184). The following methodsmay be used for adjusting the affinity of an antibody and forcharacterizing a CDR. One way of characterizing a CDR of an antibodyand/or altering (such as improving) the binding affinity of apolypeptide, such as an antibody, is termed “library scanningmutagenesis.” Generally, library scanning mutagenesis works as follows.One or more amino acid position in the CDR is replaced with two or more(such as 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or20) amino acids. This generates small libraries of clones (in someembodiments, one for every amino acid position that is analyzed), eachwith a complexity of two or more members (if two or more amino acids aresubstituted at every position). Generally, the library also includes aclone comprising the native (unsubstituted) amino acid. A small numberof clones, for example, about 20-80 clones (depending on the complexityof the library), from each library can be screened for bindingspecificity or affinity to the target polypeptide (or other bindingtarget), and candidates with increased, the same, decreased, or nobinding are identified. Binding affinity may be determined using Biacoresurface plasmon resonance analysis, which detects differences in bindingaffinity of about 2-fold or greater. Biacore can be particularly usefulwhen the starting antibody already binds with a relatively highaffinity, for example, a K_(D) of about 10 nM or lower.

In some instances, an antibody or antigen-binding fragment isbi-specific or multi-specific and can specifically bind to more than oneantigen. In some cases, such a bi-specific or multi-specific antibody orantigen-binding fragment can specifically bind to 2 or more differentantigens. In some cases, a bi-specific antibody or antigen-bindingfragment can be a bivalent antibody or antigen-binding fragment. In somecases, a multi specific antibody or antigen-binding fragment can be abivalent antibody or antigen-binding fragment, a trivalent antibody orantigen-binding fragment, or a quatravalent antibody or antigen-bindingfragment.

An antibody or antigen-binding fragment herein can be an isolated,purified, recombinant, or synthetic.

As used herein, the term “affinity” refers to the equilibrium constantfor the reversible binding of two agents and is expressed as K_(D). Thebinding affinity (K_(D)) of a SH antibody or antigen-binding fragmentherein can be less than 50 nM, 49 nM, 48 nM, 47 nM, 46 nM, 45 nM, 44 nM,43 nM, 42 nM, 41 nM, 40 nM, 39 nM, 38 nM, 37 nM, 36 nM, 35 nM, 34 nM, 33nM, 32 nM, 31 nM, 30 nM, 29 nM, 28 nM, 27 nM, 26 nM, 25 nM, 24 nM, 23nM, 22 nM, 21 nM, 20 nM, 19 nM, 18 nM, 17 nM, 16 nM, 15 nM, 14 nM, 13nM, 12 nM, 11 nM, 10 nM, 9 nM, 8 nM, 7 nM, 6 nM, 5 nM, 4 nM, 3 nM, 2 nM,1 nM, 990 pM, 980 pM, 970 pM, 960 pM, 950 pM, 940 pM, 930 pM, 920 pM,910 pM, 900 pM, 890 pM, 880 pM, 870 pM, 860 pM, 850 pM, 840 pM, 830 pM,820 pM, 810 pM, 800 pM, 790 pM, 780 pM, 770 pM, 760 pM, 750 pM, 740 pM,730 pM, 720 pM, 710 pM, 700 pM, 690 pM, 680 pM, 670 pM, 660 pM, 650 pM,640 pM, 630 6M, 620 pM, 610 pM, 600 pM, 590 pM, 580 pM, 570 pM, 560 pM,550 pM, 540 pM, 530 pM, 520 pM, 510 pM, 500 pM, 490 pM, 480 pM, 470 pM,460 pM, 450 pM, 440 pM, 430 pM, 420 pM, 410 pM, 400 pM, 390 pM, 380 pM,370 pM, 360 pM, 350 pM, 340 pM, 330 pM, 320 pM, 310 pM, 300 pM, 290 pM,280 pM, 270 pM, 260 pM, 250 pM, 240 pM, 230 pM, 220 pM, 210 pM, 200 pM,190 pM, 180 pM, or any integer therebetween.

Binding affinity may be determined using surface plasmon resonance(SPR), Kinexa Biocensor, scintillation proximity assays, enzyme linkedimmunosorbent assay (ELISA), ORIGEN immunoassay (IGEN), fluorescencequenching, fluorescence transfer, yeast display, or any combinationthereof. Binding affinity may also be screened using a suitablebioassay.

As used herein, the term “avidity” refers to the resistance of a complexof two or more agents to dissociation after dilution. Apparentaffinities can be determined by methods such as an enzyme linkedimmunosorbent assay (ELISA) or any other technique familiar to one ofskill in the art. Avidities can be determined by methods such as aScatchard analysis or any other technique familiar to one of skill inthe art.

An antibody or antigen-binding fragment can be modified by making one ormore substitutions in the amino acid sequence using a conservative or anon-conservative substitution such that the resulting modified antibodyexhibits about 80% homology to a sequence herein.

The phrase “conservative amino acid substitution” refers to grouping ofamino acids on the basis of certain common properties. A functional wayto define common properties between individual amino acids is to analyzethe normalized frequencies of amino acid changes between correspondingproteins of homologous organisms (Schulz, G. E. and R. H. Schirmer,Principles of Protein Structure, Springer-Verlag). According to suchanalyses, groups of amino acids may be defined where amino acids withina group exchange preferentially with each other, and therefore resembleeach other most in their impact on the overall protein structure.Examples of amino acid groups defined in this manner include:

(i) a charged group, consisting of Glu and Asp, Lys, Arg and His;

(ii) a positively-charged group, consisting of Lys, Arg and His;

(iii) a negatively-charged group, consisting of Glu and Asp;

(iv) an aromatic group, consisting of Phe, Tyr and Trp;

(v) a nitrogen ring group, consisting of His and Trp;

(vi) a large aliphatic non-polar group, consisting of Val, Leu and Ile;

(vii) a slightly-polar group, consisting of Met and Cys;

(viii) a small-residue group, consisting of Ser, Thr, Asp, Asn, Gly,Ala, Glu, Gln and Pro;

(ix) an aliphatic group consisting of Val, Leu, Ile, Met and Cys; and

(x) a small hydroxyl group consisting of Ser and Thr.

In addition to the groups presented above, each amino acid residue mayform its own group, and the group formed by an individual amino acid maybe referred to simply by the one and/or three letter abbreviation forthat amino acid commonly used in the art as described above.

A “conserved residue” is an amino acid that is relatively invariantacross a range of similar proteins. Often conserved residues will varyonly by being replaced with a similar amino acid, as described above for“conservative amino acid substitution.”

The letter “x” or “xaa” as used in amino acid sequences herein isintended to indicate that any of the twenty standard amino acids may beplaced at this position unless specifically noted otherwise.

As used herein, “identity” means the percentage of identical nucleotideor amino acid residues at corresponding positions in two or moresequences when the sequences are aligned to maximize sequence matching,i.e., taking into account gaps and insertions. Identity can be readilycalculated by known methods, including but not limited to thosedescribed in Computational Molecular Biology, Lesk, A. M., ed., OxfordUniversity Press, New York, 1988; Biocomputing: Informatics and GenomeProjects, Smith, D. W., ed., Academic Press, New York, 1993; ComputerAnalysis of Sequence Data, Part I, Griffin, A. M., and Griffin, H. G.,eds., Humana Press, New Jersey, 1994; Sequence Analysis in MolecularBiology, von Heinje, G., Academic Press, 1987; and Sequence AnalysisPrimer, Gribskov, M. and Devereux, J., eds., M Stockton Press, New York,1991; and Carillo, H., and Lipman, D., SIAM J. Applied Math., 48: 1073(1988). Methods to determine identity are designed to give the largestmatch between the sequences tested. Moreover, methods to determineidentity are codified in publicly available computer programs. Computerprogram methods to determine identity between two sequences include, butare not limited to, the GCG program package (Devereux, J., et al.,Nucleic Acids Research 12(1): 387 (1984)), BLASTP, BLASTN, and FASTA(Altschul, S. F. et al., J. Molec. Biol. 215: 403-410 (1990) andAltschul et al. Nuc. Acids Res. 25: 3389-3402 (1997)). The BLAST Xprogram is publicly available from NCBI and other sources (BLAST Manual,Altschul, S., et al., NCBI NLM NIH Bethesda, Md. 20894; Altschul, S., etal., J. Mol. Biol. 215: 403-410 (1990). The well-known Smith Watermanalgorithm may also be used to determine identity. Ranges of desireddegrees of sequence identity across a CDR, a FR, a VH, and/or a VL, afragment, etc. are from about 80% to about 100% and integer valuestherebetween. In general, this disclosure encompasses sequences withabout 80%, about 81%, about 82%, about 83%, about 84%, about 85%, about86%, about 87%, about 88%, about 89%, about 90%, about 91%, about 92%,about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, orabout 99%, sequence identity with any sequence provided herein. Theletter “X” or the term “Xaa” as used in an amino acid sequence herein isintended to indicate that any of the twenty standard amino acids may beplaced at this position, unless specifically noted otherwise.

“Polynucleotide” or “nucleic acid,” as used interchangeably herein,refer to polymers of nucleotides of any length, and include DNA and RNA.The nucleotides can be deoxyribonucleotides, ribonucleotides, modifiednucleotides or bases, and/or their analogs, or any substrate that can beincorporated into a polymer by DNA or RNA polymerase. A polynucleotidemay comprise modified nucleotides, such as methylated nucleotides andtheir analogs. If present, modification to the nucleotide structure maybe imparted before or after assembly of the polymer. The sequence ofnucleotides may be interrupted by non-nucleotide components. Apolynucleotide may be further modified after polymerization, such as byconjugation with a labeling component. Other types of modificationsinclude, for example, “caps,” substitution of one or more of thenaturally-occurring nucleotides with an analog, internucleotidemodifications such as, for example, those with uncharged linkages (e.g.,methyl phosphonates, phosphotriesters, phosphoamidates, carbamates,etc.) and with charged linkages (e.g., phosphorothioates,phosphorodithioates, etc.), those containing pendant moieties, such as,for example, proteins (e.g., nucleases, toxins, antibodies, signalpeptides, ply-L-lysine, etc.), those with intercalators (e.g., acridine,psoralen, etc.), those containing chelators (e.g., metals, radioactivemetals, boron, oxidative metals, etc.), those containing alkylators,those with modified linkages (e.g., alpha anomeric nucleic acids, etc.),as well as unmodified forms of the polynucleotide(s). Further, any ofthe hydroxyl groups ordinarily present in the sugars may be replaced,for example, by phosphonate groups, phosphate groups, protected bystandard protecting groups, or activated to prepare additional linkagesto additional nucleotides, or may be conjugated to solid supports. The5′ and 3′ terminal OH can be phosphorylated or substituted with aminesor organic capping group moieties of from 1 to 20 carbon atoms. Otherhydroxyls may also be derivatized to standard protecting groups.Polynucleotides can also contain analogous forms of ribose ordeoxyribose sugars including, for example, 2′-O-methyl-, 2′-O-allyl,2′-fluoro- or 2′-azido-ribose, carbocyclic sugar analogs, alpha-anomericsugars, epimeric sugars such as arabinose, xyloses, or lyxoses, pyranosesugars, furanose sugars, sedoheptuloses, acyclic analogs, and abasicnucleoside analogs such as methyl riboside. One or more phosphodiesterlinkages may be replaced by alternative linking groups. Thesealternative linking groups include, but are not limited to, embodimentswherein phosphate is replaced by P(O)S (“thioate”), P(S)S (“dithioate”),(O)NR₂ (“amidate”), P(O)R, P(O)OR′, CO, or CH₂ (“formacetal”), in whicheach R or R′ is independently H or substituted or unsubstituted alkyl(1-20 C) optionally containing an ether (—O—) linkage, aryl, alkenyl,cycloalkyl, cycloalkenyl, or araldyl. Not all linkages in apolynucleotide need be identical. The preceding description applies toall polynucleotides referred to herein, including RNA and DNA.

In one aspect, provided herein is one or more RNA molecules that encodeone or more of the antibodies or antigen-binding fragments herein. Suchone or more RNA molecules may be present in a vector for administrationto a subject.

Provide herein are polynucleotides (such as RNA, for example mRNA)encoding antibodies or antigen-binding fragments that can specificallybind to SARS-CoV-2. Antibody or antigen-binding fragments encoded bypolynucleotides can include antibodies or antigen-binding fragments.Polynucleotides can be administered to a subject to prevent infection ofthe subject by SARS-Cov-2 or to treat a subject infected by SARS-CoV-2.In some cases, antibodies or antigen-binding fragments can be producedin a subject that has been administered a polynucleotide herein.

Polynucleotides can comprise genetic material encoding an antibody orantigen-binding fragment (e.g., DNA or mRNA). In some cases,polynucleotides can be in a vector, such as a viral vector or anartificial chromosome such as a human artificial chromosome. In somecases, polynucleotides can additionally comprise a promoter, aterminator, a sequence encoding a tag, a sequence encoding a secondantibody or antigen-binding fragment, or a sequence encoding a moleculethat can aid in folding or function of the antibody or antigen-bindingfragment.

In some cases, polynucleotides can be used to prevent and/or treatdisease caused by SARS-Cov-2 or a similar virus (e.g., COVID-19); i.e.,polynucleotides can have prophylactic or therapeutic uses, or bothprophylactic and therapeutic uses. Accordingly, the present disclosureprovides methods to prevent and/or treat infection by SARS-CoV-2. Insome cases, such methods can comprise administering to a subject one ormore mRNA molecules encoding a antibody or antigen-binding fragment thatcan specifically bind to SARS-CoV-2.

An antibody library herein can comprise a plurality of antibodies and/orantigen-binding fragments. The plurality of antibodies and/orantigen-binding fragments can be at least 1.0×10⁶, 1.0×10⁷, 1.0×10⁸,1.0×10⁹, 1.0×10¹⁰, 2.0×10¹⁰, 3.0×10¹⁰, 4.0×10¹⁰, 5.0×10¹⁰, 6.0×10¹⁰,7.0×10¹⁰, 8.0×10¹⁰, 9.0×10¹⁰, or 10.0×10¹⁰.

The practice of the present invention will employ, unless otherwiseindicated, conventional techniques of molecular biology (includingrecombinant techniques), microbiology, cell biology, biochemistry andimmunology, which are within the skill of the art. Such techniques areexplained fully in the literature, such as, Molecular Cloning: ALaboratory Manual, second edition (Sambrook et al., 1989) Cold SpringHarbor Press; Oligonucleotide Synthesis (M. J. Gait, ed., 1984); Methodsin Molecular Biology, Humana Press; Cell Biology: A Laboratory Notebook(J. E. Cellis, ed., 1998) Academic Press; Animal Cell Culture (R. I.Freshney, ed., 1987); Introduction to Cell and Tissue Culture (J. P.Mather and P. E. Roberts, 1998) Plenum Press; Cell and Tissue Culture:Laboratory Procedures (A. Doyle, J. B. Griffiths, and D. G. Newell,eds., 1993-1998) J. Wiley and Sons; Methods in Enzymology (AcademicPress, Inc.); Handbook of Experimental Immunology (D. M. Weir and C. C.Blackwell, eds.); Gene Transfer Vectors for Mammalian Cells (J. M.Miller and M. P. Cabs, eds., 1987); Current Protocols in MolecularBiology (F. M. Ausubel et al., eds., 1987); PCR: The Polymerase ChainReaction, (Mullis et al., eds., 1994); Current Protocols in Immunology(J. E. Coligan et al., eds., 1991); Short Protocols in Molecular Biology(Wiley and Sons, 1999); Immunobiology (C. A. Janeway and P. Travers,1997); Antibodies (P. Finch, 1997); Antibodies: a practical approach (D.Catty., ed., IRL Press, 1988-1989); Monoclonal antibodies: a practicalapproach (P. Shepherd and C. Dean, eds., Oxford University Press, 2000);Using antibodies: a laboratory manual (E. Harlow and D. Lane (ColdSpring Harbor Laboratory Press, 1999); and The Antibodies (M. Zanettiand J. D. Capra, eds., Harwood Academic Publishers, 1995).

EXAMPLES

The application may be better understood by reference to the followingnon-limiting examples, which are provided as exemplary embodiments ofthe application. The following examples are presented in order to morefully illustrate embodiments and should in no way be construed, however,as limiting the broad scope of the application.

Example 1: Kinetics and Affinity Determination of an Anti-SARS-Cov-2scFvby Surface Plasmon Resonance

High-throughput surface plasmon resonance (SPR) kinetic experiments wereperformed on Carterra LSA Array SPR instrument (Carterra, Salt LakeCity, Utah) equipped with HC200M sensor chip (catalog No. 4287,Carterra, Salt Lake City, Utah) at 25° C. Anti-SARS-Cov-2 scFvconstructs were expressed with a V5 epitope tag to enable capture viaimmobilized anti-V5 antibody. Surfaces were prepared in HBSTE (10 mMHEPES pH 7.4, 150 mM NaCl, 3 mM EDTA, 0.01% (v/v) Tween-20) as runningbuffer. The capture surface was prepared by standard amine-coupling ofanti-V5 tag antibody (catalog No. ab27671, Abcam, Cambridge, Mass.) onthe entire chip surface as follows. The chip was activated with a 10-mininjection of a freshly prepared 1:1:1 (v/v/v) mixture of 0.4 M1-Ethyl-3-(3-Dimethylaminopropyl) carbodiimide hydrochloride (EDC)+0.1 MN-hydroxysulfosuccinimide (sNHS)+0.1 M 2-(N-morpholino) ethanesulfonicacid (MES) pH 5.5. Then, anti-V5 tag antibody was diluted to 50 μg/ml in10 mM sodium acetate pH 4.3 and coupled for 14 min. Excess reactiveesters were blocked with a 10-min injection of 1 M ethanolamine HCl pH8.5. A library of anti-COVID-19 scFv clones was supplied as plates ofcrude bacterial periplasmic extracts (PPE) and diluted 2-fold in runningbuffer. ScFv samples were flow printed for 15-min in batches of 96 PPE'sin parallel using the 96 channel printhead to generate a 384-ligandarray comprising 1 spot per scFv. For the interaction analysis, therunning buffer HBST (10 mM HEPES pH 7.4, 150 mM NaCl, 0.01% (v/v)Tween-20) was supplemented with 0.5 mg/ml BSA. Surfaces were stabilizedwith seven to eight buffer analyte injections. SARS-CoV-2, SARS-CoV-1,and MERS Receptor Binding Domain (RBD) proteins were prepared atconcentrations of 0, 3.7, 11.1, 33.3, 100, 37, and 300 nM and thesesamples were injected as analyte for 5 min, allowing a 15-mindissociation time. Samples were injected in ascending concentrationwithout any regeneration in between them. Binding data from the localreference spots were subtracted from the active spots and the nearestbuffer blank analyte responses were subtracted to double-reference thedata. The double-referenced data were fitted to a simple 1:1 Langmuirbinding model in Carterra's Kinetic Inspection Tool to give kinetics(k_(d), k_(d)), affinity (K_(D)), and R_(max) value for eachinteraction.

Captures RL ka KD Rmax Clone ID (RU) (M-1 s-1) kd (s-1) (nM) (RU)COVID19_P23_F10 1552 9.80E+04 7.70E−04 7.86 65.79 COVID19_P24_H06 17091.20E+05 5.70E−05 0.5 21 COVID19_P24_F11 1531 6.16E+05 2.80E−04 0.46 18COVID19_P23_G11 1872 2.94E+04 1.08E−04 3.67 20.39 COVID19_P24_D09 18251.14E+05 5.70E−05 0.5 19 COVID19_P11_H02 1609 3.20E+05 7.10E−04 2.2 25COVID19_P24_C06 1514 2.28E+05 5.70E−05 0.3 31 COVID19_P12_B07 16411.78E+05 5.70E−05 0.32 17.8 COVID19_P24_H04 2116 1.70E+05 6.80E−04 4 91COVID19_P23_G10 1629 1.54E+05 5.70E−05 0.37 8.72 COVID19_P24_A09 14321.52E+05 2.29E−04 1.51 51 C0V1D19_P11_D12 1756 7.90E+04 3.40E−04 4.3 74C0V1D19_P24_A11 1435 1.58E+05 3.08E−04 1.95 20 C0V1D19_P24_C10 13565.53E+05 4.87E−04 0.88 48 C0V1D19_P11_D08 1294 1.10E+05 5.30E−04 4.7 41C0V1D19_P24_E02 1507 2.09E+05 8.36E−04 4.01 109 C0V1D19_P23_H10 20255.53E+04 5.70E−05 1.03 9.63 C0V1D19_P24_G06 1742 3.70E+05 1.92E−04 0.5235 COVID19_P24_C01 1478 3.28E+05 3.22E−04 0.98 18 COVID19_P24_G09 17083.29E+05 5.12E−04 1.56 33 COVID19_P24_D08 1532 5.65E+05 4.10E−04 0.73 31COVID19_P11_H07 1734 1.10E+05 5.70E−05 0.5 39 COVID19_P11_G03 15329.90E+04 6.40E−04 6.45 40 COVID19_P24_B09 1467 5.08E+05 1.39E−02 27.4747.99 COVID19_P23_G12 0.37

The described clones each had a superior binding affinity of less than50 nM. Moreover, some clones were found to not only bind to Sars-Cov-2,but also to MERS and/or SARS-Cov-1.

Clone ID Binding Affinity For: COVID19_P23_F10 COV2 COVID19_P24_H06 COV2COVID19_P24_F11 COV2 COVID19_P23_G11 COV2+SARS1+SARS2 COVID19_P24_D09COV2 COVID19_P11_H02 COV2 COVID19_P24_C06 COV2 COVID19_P12_B07 COV2COVID19_P24_H04 COV2 COVID19_P23_G10 COV2 COVID19_P24_A09 COV2COVID19_P11_D12 COV2 COVID19_P24_A11 COV2 COVID19_P24_C10 COV2COVID19_P11_D08 COV2 COVID19_P24_E02 COV2 COVID19_P23_H10COV2+SARS1+SARS2 COVID19_P24_G06 COV2 COVID19_P24_C01 COV2COVID19_P24_G09 COV2 COVID19_P24_D08 COV2 COVID19_P11_H07COV2+SARS1+SARS2+MERS COVID19_P11_G03 COV2 COVID19_P24_B09 COV2COVID19_P23_G12

Example 2: In Vitro Neutralization Assay for Sars-Cov-2 Virus

Production and Titration of Pseudoviruses

For pseudovirus construction, spike genes from a SARS CoV-2 virusstrain, a specific were codon-optimized for human cells and cloned intoeukaryotic expression plasmid to generate the envelope recombinantplasmids. The pseudoviruses were produced and titrated using methodssimilar, as described previously in Nie J. et al. (Emerg MicrobesInfect. 2020 December; 9(1):680-686), 293T cells were transfected withPseudo virus vector using Lipofectamine system (ThermoFisher) followingthe manufacturer's instruction. Twenty-four hours later, new media wasreplaced and after 48 h from the beginning of transfection SARS-CoV-2pseudoviruses containing culture supernatants were harvested, filtered(0.45-μm pore size, Millipore, SLHP033RB) and stored at −80° C. inaliquots until use. The 50% tissue culture infectious dose (TCID50) ofSARS-CoV-2 pseudovirus was determined using a single-use aliquot fromthe pseudovirus bank; all stocks were used only once to avoidinconsistencies that could have resulted from repeated freezing-thawingcycles. For titration of the SARS-CoV-2 pseudovirus, a 2-fold initialdilution was made in triplicates wells of 96-well culture platesfollowed by serial 3-fold dilutions (8 dilutions in total). The lastcolumn served as the cell control without the addition of pseudovirus.Then, the 96-well plates were seeded with trypsin-treated Vero E6mammalian transfectable cells adjusted to a pre-defined concentration.After 24 h incubation in a 5% CO₂ environment at 37° C., the culturesupernatant was aspirated gently to leave 100 μl in each well; then, 100μl of luciferase substrate was added to each well. Two min afterincubation at room temperature, 150 μl of lysate was transferred towhite solid 96-well plates for the detection of luminescence using amicroplate luminometer (PerkinElmer). The positive well was determinedas ten-fold relative luminescence unit (RLU) values higher than the cellbackground. The 50% tissue culture infectious dose (TCID50) wascalculated using the Reed-Muench method, as described in Nie J et al.Id. In some cases the pseudovirus included a GFP reporter instead ofLuciferase; in these cases, GFP fluorescence is measured by flowcytometry.

Pseudovirus Based Neutralization Assay

Neutralization is measured by the reduction in luciferase geneexpression or GFP gene expression as described previously Nie J et al.Id. The 50% inhibitory dilution (EC50) is defined as the dilution of thetested antibodies at which the relative light units (RLUs) were reducedby 50% compared with the virus control wells (virus+ cells) aftersubtraction of the background RLUs in the control groups with cellsonly. In brief, pseudovirus in the TCID50 determined above is incubatedwith serial dilutions of the test samples (six dilutions in a 3-foldstep-wise manner) in duplicate for 1 h at 37° C., together with thevirus control and cell control wells in triplicate. Then, freshlytrypsinized cells were added to each well. Following 24 h of incubationin a 5% CO₂ environment at 37° C., the luminescence or fluoresce(depending on the reporter gene used) is measured as described above(relating to pseudovirus titration). The EC50 values were calculatedwith non-linear regression, i.e., log (inhibitor) vs. response (fourparameters), using GraphPad Prism 8 (GraphPad Software, Inc., San Diego,Calif., USA).

Results

Neutralization was observable for the clones tested: Average Tm1 (° C.)and IC50 data for a subset of the clones was provided below:

Average IC50 IC50 [μg/mL] IC50 Tm1 [μg/mL] pseudotyped [μg/mL] Clone ID(° C.) plaque lenti neut neut COVID19_P24_H06 62 − COVID19_P24_F1174.5 + COVID19_P23_G11 74.1 0.26 COVID19_P24_D09 62.6 + COVID19_P23_G1273.7 + 15.9 COVID19_P12_B07 73.4 + COVID19_P24_C10 59.2 +COVID19_P23_H10 63.1 COVID19_P24_G06 72.8 <3 0.16 <1:16 COVID19_P24_C0168.5 + 0.92 COVID19_P24_D08 59.6 + 17 − COVID19_P11_H07 60.9COVID19_P23_G10 65.9 −

Example 3: Competition of SARS-CoV-2/ACE2 Interaction withAnti-SARS-Cov-2 scFv by Biolayer Interferometry

Competition assay of the interaction of SARS-CoV-2 with ACE2 isconducted in a classical sandwich and a premix assay format using aForteBio Octet HTX biolayer interferometry instrument (Molecular DevicesForteBio LLC, Fremont, Calif.) at 25° C. with running buffer HBST (10 mMHEPES pH 7.4, 150 mM NaCl, 0.01% (v/v) Tween-20, pH 7.4) supplementedwith 1 mg/mL BSA.

An Anti-V5 tag antibody (catalog No. ab27671, Abcam, Cambridge, Mass.)is biotinylated with a 5:1 molar ratio of sulfo-NHS-LC-LC-biotin(catalog No. 21338, ThermoFisher Scientific, Waltham, Mass.) and bufferexchanged into PBS using ThermoFisher Zeba 7K MWCO columns (catalog No.89883, ThermoFisher Scientific, Waltham, Mass.).

Streptavidin sensor tips (catalog no. 18-5021, Molecular DevicesForteBio LLC, Fremont, Calif.) are equilibrated in buffer for 10-minbefore the run. Sample plates are agitated at 1000 rpm. At the start ofthe run, sensors are exposed to buffer for 60 sec to establish abaseline. The biotinylated anti-V5 tag antibody at 7 μg/mL are loadedonto the sensors for 5-min to prepare an anti-V5 surface. To blockremaining free biotin binding sites, all sensors are exposed for 5-minwith 20 μM amine-PEG2-biotin (catalog No. 21346, ThermoFisherScientific, Waltham, Mass.) followed by two alternating 30-sec cycles of10 mM glycine-HCl pH1.7 and buffer to precondition the sensors.

For the classical sandwich assay format, a baseline in buffer isestablished for 60-sec and anti-SARS-Cov-2 scFv clones as PPE undilutedare captured for 2-min onto the anti-V5 sensor tips. Baseline in bufferis recorded for 60-sec followed by association of SARS-Cov-2 at 100 nMfor 2-min, a quick wash in buffer for 15-sec, and sandwiching of 500 nMACE2 or buffer for 2-min. After each classical sandwich cycle, sensorsare regenerated with two alternating 30-sec cycles of 10 mM glycine-HClpH1.7 and buffer.

For the premix assay format, a baseline in buffer is established for60-sec and anti-SARS-Cov-2 scFv clones as PPE undiluted are captured for2-min onto the anti-V5 sensor tips. Baseline in buffer is recorded for60-sec followed by association of buffer, a premixed complex of 100 nMSARS-Cov-2+500 nM ACE2, or 100 nM SARS-Cov-2. Dissociation in buffer ismeasured for 30-sec. After each binding cycle, sensors are regeneratedwith two alternating 30-sec cycles of 10 mM glycine-HCl pH1.7 andbuffer. Capture of biotinylated ACE2 at 10 μg/mL is included as aself-blocking control in both assays.

Example 4: In Vivo Hamster Model for Sars-COV2 Infections

Competent 6-8 weeks old Syrian golden hamsters females (Charles RiverLaboratories or Harlan Laboratories) are housed three per cage in abiosafety level 3-4 animal facility in UTMB Galveston. Animals will beacclimatized in the BSL-3-4 biosafety containment 3-5 days before theexperiment begins. Animal will be housed and treated as recommended byInstitutional Biosafety and the Institutional Animal Care and UseCommittees.

Animals are injected IP with 0.5-1 mL of either saline, a therapeuticantibody at 10 mg/Kg (as disclosed herein), or an isotype controlantibody at 10 mg/Kg, 24 h before viral infection. Animals areacclimatized in the ABSL-3 biosafety containment. On the day ofinfection, hamsters (5 per group) will be inoculated with PBS or 10E5(1×10⁵) virus load via nasal cavity in a total volume of 100 μL (50 μLinto each naris).

Hamsters' bodyweight and viable signs (such as ruffled hair and lack ofmovement) will be monitored and recorded twice daily for 3 days andvirus titers will be measured from a nasal swab on day 2. Hamsters willbe sacrificed on day 3 and virus titers in homogenates of lung tissueswill be determined.

H&E-stained lung tissues will be evaluated by a suitable scientist,medical professional, or veterinary professional (e.g., trained inpathology) to determine the severity of infection and amount ofprotection provided by the neutralizing antibodies. To determine theTCID50 in the lungs, tissues will be homogenized and spun down and thesupernatants will be removed and analyzed by a TCID50 assay as describedin a previous Example, above.

Example 5: Generation of a SuperHuman Library (SHL) 2.0

A superhuman library is generated using the following steps:

-   -   1. The best 4 VH and best 4 VK frameworks from a human        repertoire of 3500 combinations (IGHV1-46, IGHV1-69, IGHV3-15,        IGHV3-23 for heavy and IGKV1-39, IGKV2-28, IGKV3-15, IGKV4-1 for        light) are selected based on a combination of 1) previous        demonstrated safety in human mAbs, 2) thermostability, 3) not        aggregation prone, 4) a single dominant allele in the frameworks        at the amino acid level across all human populations (i.e., not        a racist medicine), 5) different canonical topologies of the        CDRs, and/or 6) express well in bacteria and display well on        phage.    -   2. Blood is obtained from 140 subjects.    -   3. Naïve (CD27−/IgM+) cells and memory (CD27+/IgG+) cells are        sorted from the blood.    -   4. Pools are checked for quality using next generation        sequencing (NGS), and pools with problematic diversity or        biochemical liabilities are rejected.    -   5. VH CDR3 sequences from naïve cells are PCR amplified with        universal primers.    -   6. VH CDR1, VH CDR2, VL CDR1, VL CDR2, and VL CDR3 sequences        from memory cells are PCR amplified with framework specific        primers.    -   7. Order frameworks as synthetically produced germline segments.    -   8. Nucleic acid libraries are assembled using PCR-OE.    -   9. The assemblies from step 8 are checked for quality using NGS        sequencing.    -   10. Light chains are cloned into a vector with a stuffer VH.    -   11. In-frame material is selected by protein A or protein L        after thermal pressure.    -   12. Heavy chains are cloned into the vector to replace the        stuffer VH.    -   13. Microbes are transformed with the vectors generated at the        end of step 12 using electroporation.

Example 6: Screening for Affinity to SARS CoV-2 Receptor Binding Domain

A primary screen of two 96-well plates of clones randomly selected afterround 4 SuperHuman panning of SARS CoV-2.

Samples are immediately assayed on Carterra high-throughput kineticsinstrument, bypassing ELISA screening. A majority of the hits arepositive and sequenced, unique sequences are obtained.

Clones showing affinity to SARS CoV-2 are confirmed against human andcynomolgus monkey.

Example 7: SARS CoV-2 ELISA and Sanger Screening of 2 Plates of AntibodyClones

An ELISA panning antibody clones from two plates against SARS CoV-2 iscarried out.

Sanger sequencing of these clones is also carried out. Extreme diversityof round 3 outputs ensured that hits against any epitope can berecovered by screening a few 96-well plates of clones.

Diversity is found not only in the VH CDR3 sequences, but also in the VHCDR1 and VH CDR2 sequences.

Example 8: Combining Design and Selection Processes to Produce anAntibody Library with Diverse VII and VK Sequences

Functional selection for expression and thermostability duringconstruction is applied to produce a library with over 95% functionaldiversity across 40 million light chains. The antibody library iscreated with 7.6×10¹⁰ transformants.

First, a VK (kappa light chain) library is produced by cloning into avector the desired light chain and temporary stuffer VH sequence. The VKlibrary is displayed and subjected to a heat stress at over 65° C.In-frame material is selected using protein A/L. The stuffer VH sequencein the library resulting from the protein A/L, selection is replacedwith the target VH sequence.

Example 9: Generation of a SuperHuman Library (SHL) 3.0

A superhuman library is generated using the following steps:

-   -   1. Six antibody frameworks (IGHV1-46, IGHV3-23, IGKV1-39,        IGKV2-28, IGKV3-15, and IGKV4-1) are selected based on a        combination of 1) previous demonstrated safety in human mAbs, 2)        thermostability, 3) not aggregation prone, 4) a single dominant        allele in the frameworks at the amino acid level across all        human populations (i.e. not a racist medicine), 5) different        canonical topologies of the CDRs, and/or 6) express well in        bacteria and display well on phage.    -   2. Blood is obtained from 50-100 subjects.    -   3. Naïve (CD27−/IgM+ or CD27−/IgD+) cells and memory cells are        sorted from the blood.    -   4. Pools are checked for quality using next generation        sequencing (NGS), and pools with problematic diversity or        biochemical liabilities are rejected.    -   5. VH CDR3 sequences from naïve cells are PCR amplified with        universal primers.    -   6. Favorable VH CDR1, VH CDR2, VL CDR1, VL CDR2, and VL CDR3        sequences without liabilities are selected by DNA synthesis        based on (1) being observed present in human natural        antibodies, (2) being observed not under-performing under        selection of SuperHuman 2.0 against a variety of antigens, (3)        being free of biochemical liabilities (C, exposed M, deamination        sites, acid hydrolysis sites, N-linked glycosylation sites,        amber stop codons, opal stop codons, highly positively        charged), (4) not being more mutated than a threshold (e.g., no        more than 3 amino acid mutations per CDR). Stated differently,        VH CDR1, VHCDR2, VL CDR1, VL CDR2, and VL CDR3 sequences are        synthesized if they meet the following criteria:        -   a. have no more than 4 amino acid mutations away from the            respective germline CDR for the respective framework used;            and        -   b. are identified as present in at least 2 of the subjects            during NGS and are enriched without a fitness disadvantage            when evaluating a pool of 55,000 hits against 11 antigens            from SuperHuman 2.0, or have not been observed in a person            but to have heavily enriched during panning in the same            SuperHuman 2.0 pool; and        -   c. do not contain any biochemical liabilities (N-linked            glycosylation, deamination, acid hydrolysis, positive charge            endopeptidic cleavage, free cysteines, free methionines,            alternative stop codons, cryptic splice sites, tev cleavage            sites, or overly positively charged CDRs).    -   7. Order frameworks as synthetically produced 100% germline        segments with no mutations.    -   8. Nucleic acid libraries are assembled using PCR-OE or another        method for DNA assembly.    -   9. The assemblies from step 8 are checked for quality using NGS        sequencing.    -   10. Light chains are cloned into a vector with a stuffer VH    -   11. In-frame material is selected by protein A or protein L        after thermal pressure.    -   12. Heavy chains are cloned into the vector to replace the        stuffer VH.    -   13. Microbes are transformed with the vectors generated at the        end of step 12 using electroporation.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention herein maybe employed in practicing the invention. It is intended that thefollowing claims define the scope of the invention and that methods andstructures within the scope of these claims and their equivalents becovered thereby.

What is claimed is:
 1. An antibody or an antigen-binding fragment thatselectively binds to a severe acute respiratory syndrome coronavirus 2(SARS-CoV-2), that comprises a variable heavy chain (VH) complementaritydetermining region 1 (CDR1) having an amino acid sequence of SEQ ID NO:214; a VH CDR2 having an amino acid sequence of SEQ ID NO: 262; a VHCDR3 having an amino acid sequence of SEQ ID NO: 310; a variable lightchain (VL) CDR1 having an amino acid sequence of SEQ ID NO: 46; a VLCDR2 having an amino acid sequence of SEQ ID NO: 94; and a VL CDR3having an amino acid sequence of SEQ ID NO:
 142. 2. The antibody or theantigen-binding fragment of claim 1, that comprises a VH having an aminoacid sequence that is at least 90% identical to SEQ ID NO: 358 and a VLhaving an amino acid sequence that is at least 90% identical to SEQ IDNO:
 382. 3. The antibody or the antigen-binding fragment of claim 2,wherein the antibody is an IgG, an IgM, an IgE, an IgA, or an IgD, or isderived therefrom.
 4. The antibody or the antigen-binding fragment ofclaim 2, that comprises a binding affinity of less than 70 nanomolar(nM).
 5. The antibody or the antigen-binding fragment of claim 2,wherein the antigen-binding fragment comprises a Fab, a Fab′, a F(ab′)₂,a variable fragment (Fv), a triabody, a tetrabody, a minibody, abispecific F(ab′)₂, a trispecific F(ab′)₂, a diabody, a bispecificdiabody, a single chain variable fragment (scFv), a scFv-Fc, a Fab-Fc, aVHH, or a bispecific scFv.
 6. A method of preventing or treating aSARS-CoV-2 viral infection or COVID19 in a subject in need thereof,comprising administering to the subject the antibody or theantigen-binding fragment of claim
 1. 7. The method of claim 6, thatfurther comprises administering one or more additional therapies ordrugs to the subject.
 8. A method of diagnosing a subject as beinginfected with a SARS-CoV-2 virus or suspected of being infected with aSARS-CoV-2 virus, the method comprising contacting a sample obtainedfrom the subject with the antibody or the antigen-binding fragment ofclaim 1; detecting the presence or absence of an antibody/SARS-CoV-2virus complex or an antigen-binding fragment/SARS-CoV-2 virus complex;and diagnosing the subject as being infected with a SARS-CoV-2 viruswhen the presence of the antibody/SARS-CoV-2 virus complex or theantigen-binding fragment/SARS-CoV-2 virus complex is detected.
 9. Themethod of claim 8, wherein the sample comprises a nasal swab, a tissuesample, saliva, or blood.
 10. The method of claim 8, wherein detectingthe presence or absence of the antibody/SARS-CoV-2 virus complex or theantigen-binding fragment/SARS-CoV-2 virus complex comprises an enzymelinked immunosorbent assay (ELISA), an immunospot assay, a lateral flowassay, flow cytometry, immunohistochemistry, or a western blot.
 11. Theantibody or the antigen-binding fragment of claim 2, that selectivelybinds to a receptor binding domain (RBD) of SARS-CoV-2, wherein the RBDcomprises an amino acid sequence of SEQ ID NO:
 494. 12. An antibody oran antigen-binding fragment that selectively binds to a SARS-CoV-2, thatcomprises: (i) a VH CDR1 having an amino acid sequence of SEQ ID NO:200, a VH CDR2 having an amino acid sequence of SEQ ID NO: 248, a VHCDR3 having an amino acid sequence of SEQ ID NO: 296, a VL CDR1 havingan amino acid sequence of SEQ ID NO: 32, a VL CDR2 having an amino acidsequence of SEQ ID NO: 80, and a VL CDR3 having an amino acid sequenceof SEQ ID NO: 128; (ii) a VH CDR1 having an amino acid sequence of SEQID NO: 430, a VH CDR2 having an amino acid sequence of SEQ ID NO: 431, aVH CDR3 having an amino acid sequence of SEQ ID NO: 429, a VL CDR1having an amino acid sequence of SEQ ID NO: 432, a VL CDR2 having anamino acid sequence of SEQ ID NO: 433, and a VL CDR3 having an aminoacid sequence of SEQ ID NO: 441; or (iii) a VH CDR1 having an amino acidsequence of SEQ ID NO: 215, a VH CDR2 having an amino acid sequence ofSEQ ID NO: 263, a VH CDR3 having an amino acid sequence of SEQ ID NO:311, a VL CDR1 having an amino acid sequence of SEQ ID NO: 47, a VL CDR2having an amino acid sequence of SEQ ID NO: 95, and a VL CDR3 having anamino acid sequence of SEQ ID NO:
 143. 13. An antibody or anantigen-binding fragment that selectively binds to a SARS-CoV-2, thatcomprises a VH having an amino acid sequence of SEQ ID NO: 358 and a VLhaving an amino acid sequence of SEQ ID NO:
 382. 14. The antibody or theantigen-binding fragment of claim 1, that selectively binds to areceptor binding domain (RBD) of SARS-CoV-2, wherein the RBD comprisesan amino acid sequence of SEQ ID NO:
 494. 15. The antibody or theantigen-binding fragment of claim 1, that comprises a binding affinityof less than 70 nanomolar (nM).
 16. The antibody or the antigen-bindingfragment of claim 1, wherein the antibody is an IgG, an IgM, an IgE, anIgA, or an IgD, or is derived therefrom.
 17. The antibody or theantigen-binding fragment of claim 1, wherein the antigen-bindingfragment comprises a Fab, a Fab′, a F(ab′)₂, a variable fragment (Fv), atriabody, a tetrabody, a minibody, a bispecific F(ab′)₂, a trispecificF(ab′)₂, a diabody, a bispecific diabody, a single chain variablefragment (scFv), a scFv-Fc, a Fab-Fc, a VHH, or a bispecific scFv.